Designing the Mobile
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User Experience
Barbara Ballard, Little Springs Design, Inc., USA
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Designing the Mobile
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User Experience
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Designing the Mobile
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User Experience
Barbara Ballard, Little Springs Design, Inc., USA
Copyright © 2007 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester,
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Contents
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Preface xi
About the Author xiii
1 Introduction: Mobility is Different 1
1.1 Mobilizing Applications 2
1.2 What is ‘Mobile’ Anyhow? 3
1.3 The Carry Principle 4
1.4 Components of a Mobile Application 5
1.5 About This Book 7
2 Mobile Users in the Wild 9
2.1 Mobile User Characteristics 10
2.1.1 Mobile 10
2.1.2 Interruptible and Easily Distracted 12
2.1.3 Available 12
2.1.4 Sociable 14
2.1.5 Contextual 15
2.1.6 Identifiable 16
2.2 Groups and Tribes 17
2.2.1 Voice and Texting 17
2.2.2 Extending Online Communities 18
2.2.3 Physical and Mobile Hybrids 18
2.2.4 Mobiles as Status 19
2.3 International Differences 20
2.3.1 Europe 21
2.3.2 Japan 24
2.3.3 United States 26
2.3.4 Other Regions 28
3 Mobile Devices 31
3.1 A Device Taxonomy 31
3.1.1 General-Purpose Devices 33
3.1.2 Targeted Devices: the Information Appliance 36
3.1.3 Ubiquitous Computing 40
vi CONTENTS
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3.2 Anatomy of the PCD 44
3.2.1 The Carry Principle 44
3.2.2 Input Mechanisms 45
3.2.3 Output Mechanisms 49
3.2.4 Technologies 51
3.2.5 Connection Characteristics 54
3.2.6 Standby Screen 54
4 Selecting Application Technologies 55
4.1 Input Modalities 56
4.1.1 Buttons 56
4.1.2 Speech 57
4.1.3 Speech + Buttons 57
4.1.4 Visual + Buttons 58
4.2 Interaction Responsiveness 58
4.3 Data Storage Locations 59
4.4 Display Modality 60
4.5 Supplemental Technologies 60
4.6 Distribution Methods 62
4.6.1 Cost of Deployment 62
4.6.2 Sales Channels 63
4.7 Other Concerns 65
4.8 Platforms 66
5 Mobile Design Principles 69
5.1 Mobilize, Don’t Miniaturize 70
5.1.1 The Carry Principle 71
5.1.2 Small Device 72
5.1.3 Specialized Multi-Purpose 75
5.1.4 Personal Device 79
5.1.5 Customized Device 79
5.1.6 Always On, Always Connected 80
5.1.7 Battery-Powered 80
5.1.8 Inconsistent Connectivity 81
5.2 User Context 82
5.3 Handling Device Proliferation 83
5.3.1 Targeted Design 84
5.3.2 Least Common Denominator 85
5.3.3 Automatic Translation 86
5.3.4 Class-based Design 88
5.4 Emulators and Simulators 90
5.5 Detailed Design Recommendations 91
5.5.1 Platform Providers 91
5.5.2 Standards Organizations 92
CONTENTS vii
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5.5.3 Carriers and Device Manufacturers 92
5.5.4 Third-Party Guidelines 93
6 Mobile User Interface Design Patterns 95
6.1 About User Interface Patterns 95
6.1.1 Mobilization 96
6.1.2 Universal Patterns 100
6.1.3 Corporate Patterns (Library) 100
6.2 Screen Design 101
6.2.1 List-based Layout 101
6.2.2 Table-based Layout 102
6.2.3 Location Selection 104
6.2.4 Returned Results 105
6.2.5 Menus 107
6.2.6 Tab Navigation 109
6.2.7 Breadcrumbs 110
6.3 Application Navigation 112
6.3.1 List Navigation 112
6.3.2 Game Navigation 114
6.3.3 Alphabetic Listings – Short 116
6.3.4 Alphabetic Listings – Long 117
6.3.5 Softkey and Button Management 118
6.4 Application Management 121
6.4.1 Application Download 121
6.4.2 Application State Management 122
6.4.3 Launch Process 123
6.4.4 Cookies 124
6.5 Advertising 126
6.5.1 Interstitials 126
6.5.2 Fisheye Ads 128
6.5.3 Banners 131
7 Graphic and Media Design 133
7.1 Composition for the Small Screen 133
7.1.1 Learning from Portrait Miniatures 135
7.1.2 Distinguishing from User-generated
Content 136
7.1.3 Style and Technique 137
7.1.4 Context of Use 139
7.2 Video and Animation 140
7.2.1 Content 141
7.2.2 Production and Preprocessing 142
7.2.3 Post-production 143
viii CONTENTS
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7.3 Sound 144
7.3.1 Content 145
7.3.2 Post-production 145
7.4 Streaming versus Downloaded Content 146
7.5 Managing Media: Meta Data 147
8 Industry Players 149
8.1 Carriers (Operators) 150
8.1.1 Carriers and Devices 150
8.1.2 Walled Gardens and Decks 152
8.1.3 Mobile Virtual Network Operators 153
8.1.4 Network Types 154
8.2 Device Manufacturers 154
8.3 Technology and Platform Providers 155
8.3.1 Browsers 156
8.3.2 Application Environments 156
8.3.3 Operating Systems 157
8.3.4 Hardware and Other Software 158
8.4 Application and Content Developers 158
8.5 Content Distributors 159
8.6 Industry Associations 160
8.7 Government 161
9 Research and Design Process 163
9.1 Mobile Research Challenges 165
9.1.1 Device Proliferation 166
9.1.2 Multimodal Applications 167
9.1.3 Field versus Laboratory Testing 167
9.2 User Research 168
9.3 Design Phase Testing 169
9.3.1 Card Sorting 169
9.3.2 Wizard of Oz Testing 170
9.4 Application Usability Testing 171
9.4.1 Emulator Usability Testing 172
9.4.2 Laboratory Usability Testing 173
9.4.3 Field Usability Testing 173
9.5 Market Acceptance (beta) Testing 175
10 Example Application: Traveler Tool 177
10.1 User Requirements 177
10.1.1 User Types 178
10.1.2 User Goals 179
10.1.3 Devices 179
10.1.4 Key User Needs 179
CONTENTS ix
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10.2 Product Requirements 182
10.2.1 Features 183
10.2.2 Technologies and Platform 186
10.2.3 Device Classes 187
10.2.4 Development Strategy 187
10.3 High-level Design Concepts 188
10.3.1 Task List 189
10.3.2 Communications Center 189
10.3.3 Maps, Directions, and Transportation 190
10.3.4 Journaling 191
10.3.5 Local Information 192
10.3.6 Main Screen 193
10.3.7 Softkey Strategy 195
10.4 Detailed Design Plan 196
10.4.1 Process 196
10.4.2 Tasks 197
10.4.3 Data Sources 197
10.4.4 Testing Plan 198
Appendices 199
A: Mobile Markup Languages 199
B: Domain Names 204
C: Minimum Object Resolution 206
D: Opt-In and Opt-Out 209
E: Mobile Companies 212
Glossary 221
Index 235
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Preface
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Hundreds of devices. Dozens of browsers. Hundreds of implementation environments. Myriad technology choices text messaging,
voice-over-IP, Java, GPS, MMS, cameras, and more. Does the connectivity matter? CDMA, GSM, 1xRTT, CDMA-EDGE, GPRS, Wi-Fi,
WiMAX, Bluetooth
And let’s not forget the users. At a desk, hiding from teachers, at a
cafe, at a club. Mobile phones are used instead of lighters at concerts.
People use the mobile in the bathroom.
Mobile phones are not miniature personal computers, and mobile
applications should not be miniature computer applications. While
product design for mobile devices is not a separate discipline from
desktop computer software and web site design, it does have many
differences in users, user context, technologies, distribution, and
research.
The mobile space is complex, but navigable. While technologies
come and go, certain key principles remain the same. ‘The Carry Principle’ is the observation that the mobile phone, and any related or
future personal communications devices, are always with the user. This
simple principle strongly influences the shape of the personal communications device market, limitations users will be experiencing, context
of use, and nature of the device itself. Learn how The Carry Principle
affects application design throughout this book.
Designing the Mobile User Experience is intended to provide experienced product development professionals with the knowledge and
tools to be able to deliver compelling mobile and wireless applications.
The text could also be used in undergraduate and graduate courses as
well as any other education venue that focuses on mobile design and
the mobile experience.
While many of the principles in the book will be useful to device
manufacturers and mobile platform creators, it is largely targeted at the
vastly larger number of people designing and developing applications
to run on those devices using those platforms.
The book covers the obvious – devices, technologies, and users in
the mobile environment – but goes further. Included is a discussion
xii PREFACE
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of design patterns in the mobile space, including handling rendering
differences, in Chapter 6. Chapter 5 covers general mobile design principles and sources of more specific design recommendations. Media
generation for mobile is covered in Chapter 7. Research variations for
mobile users are covered in Chapter 9.
Chapter 8 covers the various players in the mobile value chain, and
their history, different goals, and typical decisions. Your organization will likely be in or closely related to one of these categories, and
understanding what players in the other categories are doing will help
decision making. Several application developers enter the mobile space
thinking that a web site and some viral marketing will get their application on devices, but historically this has failed. Learn who needs to
be part of your consideration.
Finally, Chapter 10 discusses an example application, from concept
to design and project management. A few appendices help navigate
topics like mobile markup languages, mobile domain names, capturing
images for mobile display, and SMS campaign best practices. Also
find a list of companies important in the mobile field and their web
addresses, and an extensive glossary of mobile terms.
I owe gratitude to my entire family and network of friends for the
ongoing support I have received in the creation of this book, especially
with a new baby in the house. My husband in particular has had his
patience sorely tested, and he has continued to support me.
Mark Wickersham and especially Elizabeth Leggett have helped with
editing throughout the book. Mark is my technology go-to man, and
Elizabeth understands users and art in a way that I simply don’t.
The two made the chapter on media possible and as good as it is.
Additionally, Elizabeth patiently reviewed every chapter, usually more
than once, and put together many of the graphics for me.
James Nyce spent several hours helping with the chapter on design
principles as well as reviewing the first chapter. C. Enrique Ortiz
graciously review some chapters near the project completion, while on
vacation. This book is the richer for their input.
About the Author
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Barbara Ballard is founder and principal of Little Springs Design,
a mobile user experience consultancy founded in 2001. Clients
have included carriers, device manufacturers, content companies, and
industry associations, with projects including platform user experience,
device UI design, style guides, and application design. Prior to 2001,
she worked at the US carrier Sprint PCS on the user experience of
devices, platforms, style guides, and data services.
Barbara has an MBA from the University of Kansas and a BS in
industrial engineering from the University of California at Berkeley. She
additionally has completed all coursework necessary for a doctorate in
human factors and ergonomics from North Carolina State University,
with significant work in engineering, psychology, and industrial design.
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1
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Introduction: Mobility is Different
A mobile phone is a Swiss Army knife. It is not a chef’s knife or a buck
knife. We keep wanting new features on the phone, like texting, voice
memos, browsing, a camera, music, and television, because we would
like these things in our pocket and the phone is already there.
And like a Swiss Army knife, the user experience of each of the
features leaves quite a bit to be desired. A Swiss Army knife will not
deliver the quality of cut a chef’s knife will, nor will it fit in the hand
quite as well as a good pocket knife.
Designing applications or web sites for mobile phones is in many
ways the same as designing the best possible screwdriver or fishing rod
for a Swiss Army knife. There is much that needs to be done before
people will actually use the application – and people will not use the
Swiss Army screwdriver in the same situations that they would use a
full-sized screwdriver.
While the platform, user context, business context, device, and technologies involved in a particular mobile application may be different
from similar desktop applications, the fundamental product design
and development practices remain the same. The purpose of this book
is to give product designers, software developers, marketers, project
managers, usability professionals, graphic designers, and other product
development professionals the tools they need to make the transition
into the mobile arena.
This is not a book about technology or specific design recommendations. Instead, it focuses on the mobile users and their context.
Designing the Mobile User Experience Barbara Ballard
© 2007 John Wiley & Sons, Ltd
2 INTRODUCTION: MOBILITY IS DIFFERENT
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It leans heavily on principles of human–computer interaction, usability,
product development, business, and graphic design.
1.1 MOBILIZING APPLICATIONS
‘I don’t have a need for data services on my phone. Just give me
a simple phone that has good reception and battery.’
I hear some variant of this from almost everybody to whom I talk
about my work who is not actually in the mobile industry – although
I grant that I do not talk to many teenagers about my work.
Focus groups show that real consumers are painfully aware that the
web sites that they use not only would not work well on a mobile
phone, but also would have little functionality or purpose. Most people
are barely willing to read a long document or news story on a relatively
comfortable full-sized monitor; it is difficult to know when or why
a person would be willing to read the same story on a tiny screen.
And willingness to pay for a service that provides text freely available
elsewhere is even more rare.
This state of affairs, which is present in some degree in most of
the world, is a result of some fundamental misunderstandings about
what mobility means for customers and users. These misunderstandings cause the frequent failure of companies to create useful, relevant,
enjoyable experiences.
Most mobile applications have been created as a miniaturized version
of similar desktop applications. They have all the limitations of the
desktop applications, all the limitations of the mobile devices, and
typically some extra limitations due to the ‘sacrifices’ designers and
developers make as they move applications from desktop to mobile
device.
Some mobile applications have broken the ‘miniaturize’ trend and
have enjoyed considerable success. While sound customization in the
desktop environment is something done only by highly motivated users,
phone ring tones have become a key component of the mobile user
experience. FOX Network’s ‘American Idol’ television show allowed
the audience to vote via text messaging, and text messaging even in the
United States has become extremely profitable.
Text messaging is very popular (and profitable), especially in Europe,
and most of Japan’s iMode traffic is actually similar short communications services. Sprint PCS did not have two-way text messaging in
WHAT IS ‘MOBILE’ ANYHOW? 3
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its earlier offerings but developed a web-based similar product which
fast became extremely profitable despite having never been advertised.
While there are several factors that these successful examples share,
the most notable thing is something they do not share: they are not
simply desktop applications ported to the mobile environment. A welldesigned mobile application, to be successful, cannot simply be some
subset of the corresponding personal computer (PC) application, but
rather an application whose features partially overlap and complement
the corresponding PC application’s features.
1.2 WHAT IS ‘MOBILE’ ANYHOW?
The definition of ‘mobile’ is slippery. Visit the Consumer Electronics
Show’s ‘Mobile’ section and you will see a plethora of in-automobile
media players, both audio and video. A laptop computer is certainly
‘mobile’ but is used more like a desktop computer.
Other attempts to apply a name to the field have used ‘wireless’, describing how the device communicates digitally. This again is
problematic as more and more desktop computers are using wireless
communications, as are automobiles, thermometers, and likely refrigerators in the future.
One of the earliest books on user-centered design in the mobile
environment has used the term ‘handheld’, which wonderfully captures
the essence of the size of the devices in question, but allows television
remote controls into the definition.
Mobile phones epitomize mobile devices, but the category also
includes personal data assistants like Palm, delivery driver data pads,
iPods, other music players, personal game players like GameBoy, book
readers, video players, and so forth. Fundamentally, ‘mobile’ refers to
the user, and not the device or the application.
Further, this book is about the business and practice of mobile user
experience management, not design for specific platforms. If you are
designing a Palm application, go see a developer guide for PalmOS. If
you are designing an iPod application, go see a developer guide for that
platform. There are a number of mobile web and Java development
guides available. These resources are invaluable.
To get entertainment and information services to the mobile user,
some sort of communications device is necessary. Most target users of
applications already have a mobile phone or other mobile communications device, which they carry with them most or all of the time.
4 INTRODUCTION: MOBILITY IS DIFFERENT
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1.3 THE CARRY PRINCIPLE
Of particular importance to mobile users are a special category of
devices, namely personal communications devices, or PCDs. These are
epitomized by mobile phones and text communications devices like
the BlackBerry and Sidekick. The principles of design and management
found in this volume apply to PCDs. In this book, the terms ‘mobile
device’ and ‘personal communications device’ are used interchangeably.
A PCD is:
•
Personal. The device generally belongs to only one person, is personally identifiable, and has a messaging address and ongoing service.
•
Communicative. The device can send and receive messages of various
forms and connect with the network in various ways.
•
Handheld. The device is portable. It can be operated with a single
hand, even if two hands or a hand and a surface are more convenient.
•
Wakable. The device can be awakened quickly by either the user or
the network.
For example, a mobile phone will receive a text message even when
in its ‘sleep’, or standby state. Note that most computers, if they are
asleep, can not communicate with the network.
This combination of features makes the service indispensable and
the PCD an ever present part of the user’s life. The service represents
safety and social connection. Because the service is indispensable, users
tend to carry the device with them all the time. This fact forms the
core of understanding the mobile user experience.
The fundamental distinction between mobile-targeted design and
design targeted for other platforms is The Carry Principle: the user
typically carries the device, all the time. The Carry Principle has several
implications on the device:
•
Form. Devices are small, battery-powered, have some type of wireless connectivity, and have small keyboards and screens (if present).
•
Features. Any information or entertainment features that might be
desirable to have away from a computer or television, including
television itself, will eventually get wedged onto the PCD. Devices
evolve towards the Swiss Army knife model.
•
Capabilities. The wireless connection, small size, and power
constraints have made devices have slower connection speeds, slower
processors, and significantly less memory than desktop computers.
COMPONENTS OF A MOBILE APPLICATION 5
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•
User interface. The small screen drives the device to a single-window
user interface, so sharing information between applications is problematic.
•
Proliferation. A personal, always-present device needs to match a
user’s needs, desires, and personality reasonably well. One form,
one feature set, one user interface will not fit all.
The Carry Principle also has implications for the PCD users:
•
User availability. The mobile user is more available for communications and application interaction than a computer user simply
because the device is always present.
•
Sustained focus. Because the user is doing so many things, there may
not be sustainable time available for the device.
•
Social behavior. Always-available connections has made attending
meetings and dinner with friends a modified experience. Coordination across space allows both more and less social behavior.
Each of the above has implications for application design.
1.4 COMPONENTS OF A MOBILE APPLICATION
Any serious consideration of the design of software starts with a consideration of where the software will be used. Designers of web sites or
applications intended for use on desktop or laptop computers tend
to ask ‘which operating system shall we target?’, as computers are so
standardized.
In reality, the desktop environment comprises a number of agreedupon characteristics. All have a largish color computer screen of at least
800 × 600 pixels, a full keyboard, a mouse, speakers, and applications
residing in windows. Connectivity may be slow (30 Kb/s) or fast (500
Mb/s or more), but it is generally there. In the US, landline network
access is generally unlimited.
Further, the user of a desktop application is sitting at a desk or at
least with a computer in the lap. There is a working surface, and both
hands and attention are focused on the computer. Interaction with
other people takes place only through the computer, not generally in
person around the computer.
Devices in the mobile environment do not play by the same rules.
This is not due to the lack of standards, but due to the highly varying
6 INTRODUCTION: MOBILITY IS DIFFERENT
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needs of mobile users. The differing capabilities of low-end mobile
phones, high-end smart phones, and alternative devices lead to a variable environment. Expect this situation to continue for a long time.
A mobile application consists of:
•
a PCD, with its own use metaphor, browser, application environment, and capabilities
•
a user, using any of a set of mobile devices, who could be riding
a train, sitting in a meeting, sitting in a restaurant, walking down
the street, focused on other tasks, or engrossed in the device and
application
•
one or more application platforms, which can include web
browsers, application environments (such as BREW, Palm, Windows
Mobile, Symbian, or Java 2 Micro Edition), messaging technologies
(including email, SMS, MMS, and instant messaging), media environments (types of music and video players), and so forth, with new
capabilities becoming available regularly
•
one or more output interfaces with the world outside the mobile
device, including screen, speaker, infrared, Bluetooth, local wireless
(Wi-Fi), cellular wireless, unique terminal identification
•
one or more input interfaces with the world outside the
mobile device, including (limited) keypad, touchscreen, microphone,
camera, RFID chip reader, global position, infrared, Bluetooth, local
wireless (Wi-Fi), cellular wireless
•
optionally a server infrastructure that complements the mobile application and adds information or functionality to the above
•
interfaces between the application’s servers and other information
sources
•
a network and the corresponding wireless carrier (operator), who
enables some of the above technologies, connects the user to the
Internet and other users, sells applications and other services, may
specify permitted devices, and frequently defines what may and may
not be accomplished on the network
In contrast, an application delivered to a personal computer operates
in a more predictable environment. Operating systems are limited to
approximately three, rather than dozens. There is one browser markup
language, and though there are rendering differences between browsers,
they are trivial and readily handled compared with mobile browsing.
Influence of any sort of the end user’s ISP is unheard of. There are
ABOUT THIS BOOK 7
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definitely complexities associated with developing for the personal
computer, but mobile is more complex in almost every dimension.
1.5 ABOUT THIS BOOK
This book is intended to help product design and development professionals make the transition from desktop to mobile with sophistication
and understanding. It covers the obvious – devices, technologies, and
users in the mobile environment – but goes further. Chapter 2 discusses
the characteristics of mobile users and how they differ from desktop
users. Chapter 3 presents a framework for understanding the range
of mobile devices and how they fit into users’ lives, then discusses
the anatomy of the personal communications device. In Chapter 4,
learn about various application presentation technologies and how to
choose the best one for a project. Chapter 5 covers general mobile
design principles and sources of more specific design recommendations.
Find sample mobile user interface design patterns in Chapter 6. Media
generation for mobile is covered in Chapter 7. Chapter 8 covers the
various players in the mobile value chain, and their history, different
goals, and typical decisions. Chapter 9 discusses modifications of a
user-centered design process for mobile applications, including modifications of user research techniques. Chapter 10 discusses an example
application, from concept to design and project management.
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2
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Mobile Users in the Wild
Consider a typical desktop – or even laptop – computer user. He is
sitting quietly, perhaps with music in the background, looking only at
the computer. Maybe he is in an airport lounge, with people swirling
all around him, but he is still focusing on the computer. When he steps
away from the machine, he is no longer connected to the network.
If a desktop user is in a busy office, interruptions likely abound.
Telephones, personal visits, and general noise could be present. Email
and instant messaging are major sources of interruption. Personal
computers and their software should be designed to work with this
social state of affairs, rather than assuming users will focus on a task
until completion. Some software is.
Mobile users may hold some surprises:
•
Adult women make up more of the mobile phone gaming market
than do any other market segment,
of teenage boy gaming dominance.
•
The formula for a successful mobile phone game usually involves
short attention, rather than a fully absorbing experience.
•
Mobile users are quite skeptical about web sites on their phone,
as anybody can clearly see that it is not the same experience as a
desktop computer.
1
Several sources, including the Telephia Mobile Game Report for Q1:2006 and Parks Asso-
ciates’ Electronic Gaming in the Digital Home (Q2:2006).
Designing the Mobile User Experience Barbara Ballard
© 2007 John Wiley & Sons, Ltd
1
breaking the precedent of years
10 MOBILE USERS IN THE WILD
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Despite the previous, an increasing number of users are interested in
television on their phones. In 2006, use is quite low, but interest was
variously reported between 11% and 30%, depending on the survey.
2.1 MOBILE USER CHARACTERISTICS
To some degree, there is no particular difference between mobile
users and the users of other devices. In fact, the low cost of mobile
devices relative to computers, particularly combined with the high cost
of laying telephone cables to remote villages, means that the mobile
phone is becoming the predominant mechanism to access information
services. Thus desktop users will soon be a subset of mobile users.
All this is true, but it misses the key point of mobility: most of the
mobile users are not sitting attentively at a desk or passively on a
sofa. They are out and about, they are social, they are moving. They
use the device for more personal purposes than a television or even a
computer: it is more likely to be used by just one person.
Figure 2.1 illustrates many of the issues of mobile users. Fashion is a
consideration. Size is important. The device is always present, always
carried. The user is interruptible.
2.1.1 Mobile
Mobile users are mobile. They may be mobile while actually using an
application, or they may move between instances of using the application. Being mobile means that user location, physical, and social
context may change, that physical resources cannot be relied upon,
and that physical world navigation may have to be accomplished.
The user may be in rush-hour traffic, in a meeting, in class, on a train,
walking down the street, at a café, at the library, or in a restroom in
unlimited, ever-shifting environments. Except for highly task-focused
applications, like discovering when the 56 bus will arrive at stop 70,
the user’s context will not be predictable. The user’s context may be
discoverable using current and future technologies.
Generally mobile users can be expected to have their wallet, keys,
and phone, and companies are working hard at making the wallet and
perhaps the keys unnecessary. What is not present is a pencil to jot
down information, a user’s files, reference books, or anything on the
desk. Information or content stored on the computer may or may not
be remotely available (typically not).
MOBILE USER CHARACTERISTICS 11
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Figure 2.1 Mobile users have different availability, context and interruptibility
than do desktop users
Navigating through the physical world, managing obstacles and
picking routes, is a task that uses a majority of a person’s attention
resources. Similarly, navigating through the virtual world, performing
text entry, and reading text, consumes cognitive resources. Because
these tasks are similar – both navigation – they clash with each
other. Typically, a user attempting both simultaneously will end up
performing the tasks in sequence, or alternating. Even when alternating
virtual and physical tasks quickly, either or both can suffer.
Shifting context and navigation conspire with other factors to make
the mobile user more interruptible and easily distracted than desktop
users.
12 MOBILE USERS IN THE WILD
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2.1.2 Interruptible and Easily Distracted
The mobile user has all the sources of interruption from the physical
world that the desktop user has, without some of the social cues that
suggest he is unavailable for interruption. He is not sitting in an office,
he is not facing a computer obviously focused on a task. He is instead
at a client’s office, at dinner, waiting for a train, in a meeting, on a date
or at a desk, among many possibilities. In many of these cases, his mere
presence in a public, social space could indicate he is interruptible. The
smaller screen size seems to block fewer people, it is easier to meet
his eyes.
He is using a device that can likely display only one thing at once, so
using open windows as reminders does not come easily. Further, even
the device can interrupt itself, with incoming calls or text messages.
Many of his distractions cannot be stalled by social cues: the train will
not wait for him to finish a task or conversation. The user therefore
has no opportunity to ‘just finish this sentence’ when interrupted. The
transition between virtual and physical tasks can be jarring and can
reduce effectiveness at both tasks.
These user characteristics have a number of immediate implications
for application architecture, especially in the area of state management. Most applications should, if not explicitly exited by the user,
return to the same view with the same data as when the user last
departed. Data should be saved without user action, possibly in a
temporary store before committing changes to the official document.
Because the user may not have an opportunity to save data, the
application must save any critical or difficult to enter data for later
reuse.
2.1.3 Available
The converse side to interruptibility is that mobile phone users are
quickly available to remote friends, family, colleagues, and clients. This
fact has led to higher job stress and less quiet time, but it also enables
people to feel more connected.
Most personal communications devices (PCDs) are with the user
constantly, either throughout the day, or throughout relevant portions
of the day. These devices are likely to go with the user even to the
restroom, particularly as they tend to be either worn or in pockets.
Many people even feel uncomfortable when uncoupled from their
MOBILE USER CHARACTERISTICS 13
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devices. Thus a characteristic of mobile users is that they are present
and immediately available. They are likely to look at their PCD even
when they are with others.
At colleges, a large percentage of pedestrians stroll through the
campus with a phone stuck to their ear, or perhaps stopping occasionally to text. No one need ever be alone. While this fosters the
sense of connection to remote friends, it is also making it more difficult for people to communicate in person. A post-class conversation
while walking to lunch is less likely to occur if all the students immediately dial to coordinate lunch with somebody else. Mobile phones are
changing the college experience.
Culture, generation, context, and personality combine to maintain
an ‘importance hierarchy’ for various interaction sources around the
user. An in-person conversation with a respected elder is likely to
trump an incoming call, but the incoming call might take precedence
over a conversation with a clerk. A call from a wife or daughter nine
months pregnant is likely to trump almost anything including lecturing
a classroom.
Being readily available means that people answer their phones, either
with voice or text, in what used to be considered inappropriate places.
Texting and even voice calls in public restrooms are becoming more
common. Accepting a phone call during a personal conversation has
become very common, and is frequently a source of tension between
different generations.
While turning off the phone, or simply not answering it, is one
popular method for dealing with the phone’s prolonged intrusion into
life, many users do not turn it off. Ethnographic research has revealed
that mobile users in Madrid think that it is rude to let a call go
unanswered, and will answer it in class, when out with friends, or
2
at the cinema.
Behavior differs from country to country and user
to user, but even a person who does not answer the phone remains
readily available. She may return the call quickly or text back, and she
immediately knows the call was made.
Availability allows applications to communicate with instant
messaging-like technologies with confidence that the user is present and
will receive the information immediately. An application that required
a return receipt from the device could ensure that a message actually
made it to the device.
2
Lasen, Amparo, 2002. A comparative study of mobile phone use in public places in London,
Madrid, and Paris. University of Surrey Digital World Research Centre.
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2.1.4 Sociable
While mobile users are available to connection from people using the
phone, they are also sociable with the people around them. The other
people in the restaurant are likely aware of any voice conversation, and
friends at the table may be excluded from an incoming connection, or
could as easily be included. A group of Japanese youth may pull out
their phones to decide where to meet for dinner.
Social behaviors will vary based on who is physically present, where
the presence is, the current mood, the type of incoming communication,
and the source of incoming communication. An application also could
be launched as part of a group activity. Consider a story:
A small group of friends sit around a dinner table, talking about
the events of the day and their friends. A phone rings. Two people
reach for their pockets, and it’s Larry’s phone. He answers the
phone, and is immediately merely ‘near’ people – he is ‘with’ the
person on the phone. The conversation at the table slows to a halt,
with some people starting to look uncomfortable. Conversation
slowly returns once Larry is off the phone.
And a variant:
A small group of friends sit around a dinner table, talking about
the events of the day and their friends. A phone rings. Two people
reach for their pockets, and it’s Larry’s phone. He discovers a text
message from his girlfriend, and he quietly chuckles. He dashes
off a response, during which time he is ‘near’ people. He re-enters
the conversation as soon as he hits send.
And finally:
A small group of friends sit around a dinner table, talking about
the events of the day and their friends. A phone rings. Two people
reach for their pockets, and it’s Larry’s phone. He discovers the
latest installment in the mobile trivia game is available and he
immediately starts the game. He reads the questions out to his
table mates, soliciting opinions and gaining laughter. They decide
to finish dinner and go discover the answer to the third question:
‘What is the title of the book being read by the statue on the West
side of the Plaza near the theater?’
MOBILE USER CHARACTERISTICS 15
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In each case Larry interacts with his phone, but he interacts differently
due to application technology (voice call, text message, interactive
game via messaging or Java), social context, and personal and cultural
proclivities.
The application type provides part of the context. A voice call
is socially and technologically assumed to be between two people;
adding extra parties is enough of a violation of normal behavior that
announcing the presence of others in the conversation is considered a
minimal requirement for politeness. Text messaging connotes a variable amount of privacy, and games have no privacy requirements.
Personal and cultural practices also provide someofthecontext.Larry
could have deferred the call until later. He could have had his phone
on silent, and made the choice based on incoming caller. He might have
deferred a social call if at lunch with his boss, and accepted a call from
the boss if at lunch with friends. He would have deferred the call if in a
Japanese train, but might have taken the call if in a Spanish theater.
Larry is managing several ‘microcontexts’ simultaneously. First, his
dinner companions provide a social context, both long-term and immediate. Their current topic of conversation might encourage acceptance
or deferral of a call. The composition of companions and the group’s
history and personalities also influence call acceptance. Second, the
larger physical environment – home, café, diner, or upscale restaurant –
guides expectations and provides another microcontext. Third, each
application – voice, text, or content – provides its own microcontext.
Finally, the personalities on the other side of the mobile connection –
girlfriend, boss, impersonal application – provide another set of microcontexts.
A social mobile user can manage several microcontexts simultaneously; other mobile users remove themselves from as many microcontexts as possible to focus on just one or two. Nevertheless all mobile
users are exposed to one or more microcontexts. Most microcontexts,
as noted above, are social microcontexts. Applications can be designed
to encourage sociability in person as well as online sociability. Sociability is a key metaphor in mobile applications, and the better it is
understood, the better the change of increasing application exposure
and driving revenue.
2.1.5 Contextual
The mobile user’s environment affects how the device is used. Ideally,
the device would know whether the user is in a meeting, on a business
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trip, snow skiing, asleep, driving, or any other activity, and would give
this information to the applications so they could behave appropriately
for the user in that environment. Devices don’t really do this yet, but
there is a lot of information potentially available to applications that
goes unused. Consider:
•
A calendar application could switch the phone’s ringer to vibrate
and intelligently communicate to the caller that the recipient is in a
meeting right now. The caller could indicate message urgency – or
leave a message or call later – and the recipient could decide whether
to accept the call.
•
A travel companion application can use the user’s location, the
flight number, current flight status, and current traffic conditions
to alert the user fifteen minutes before she needs to depart for the
airport. The same application could alert meeting attendees when
the application owner is going to be later.
•
A restaurant coupon application could send coupons at lunchtime
when the user is away from home and near restaurants.
Future devices may have acceleration sensors, temperature sensors,
fingerprint readers, and any number of other information sources we
do not currently imagine.
2.1.6 Identifiable
Because devices are personal, they are usually unique to a single user.
Exceptions to this rule are rare. This identification includes both the
unique messaging address (phone number or email address or similar)
as well as the device.
Further, in some ways the user’s messaging address is more valuable
to the user than the device itself, since it is a persistent method of
contacting the user. Not only is the user associated with the address,
but the use of the address is directly connected to how much the
user’s charges will be for the month. This value is so high that special
regulations in the United States mandate number portability between
carriers.
In theory, subscriber identification provided by the device can be
used to identify a returning user to a web site without user input. In
practice, some carriers have hidden this information to all but business partners. Web applications must use cookies to identify users.
However, even more than in the desktop world, there is a reliable
GROUPS AND TRIBES 17
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user identification for application security: phone sharing is rare, and
a missing phone is likely to be disabled so it cannot connect.
2.2 GROUPS AND TRIBES
Mobiles play a complex and evolving social role, from status symbol
to facilitator of gossip.
2.2.1 Voice and Texting
Fundamentally, the mobile makes immediate long-distance relationships, to the point that long-distance relationships can become more
relevant than the relationships with people nearby. The mobile
combines the advantages of the landline phone, with the advantages
of email, and improves upon them by being always with the user.
The idea that mobiles foster community is supported by certain
research. A study by the Social Issues Research Centre, for example,
looked at the role of mobiles as they facilitate gossip.
both as a connection method and as a mechanism of ‘social grooming’,
reinforcing what is and is not acceptable behavior and hence strengthening what is and is not part of the social group. The mobile provides
a constantly available mechanism to engage in immediate gossip about
news, public figures, or Joe in the next office over. The mobiles enable
significant social bonding: more than landline phones.
Texting adds to the social connections, but through different mechanisms and with different benefits. Teenagers can use the act of writing
to be a bit less awkward in social interactions. People can send a little
‘I’m thinking of you’ type message to others, building the community
and without the risk of a prolonged discussion or interruption. This
type of interaction is beginning to replace similar practices of interaction with the neighbors to build social bonds.
While mobiles are making at least some people less interactive
with their immediate surroundings and less social with people nearby,
they simultaneously are having a second effect. The always-available
communications reduces the risk of going somewhere alone, either
through safety concerns or through group coordination challenges.
3
Gossip is used
3
Fox, Kate, 2001. Evolution, Alienation and Gossip: The role of mobile telecommunications in the 21st century. Oxford: Social Issues Research Centre. http://www.sirc.org/publik/
gossip.shtml
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This added freedom is allowing at least some people more interaction
with a wider variety of environments and people than they otherwise
would have experienced.
2.2.2 Extending Online Communities
Add to the simple communications properties of phones a variety of
web-enabled applications that foster online communities. Myspace.com,
Flickr, and various blogging sites, for example, are becoming mobile
enabled. Users can get constant access to the communities, which frees
them from their computers a bit as well as extends the time and degree
of interaction with the services.
The process of extending an online community to mobile typically
starts with adding mobile viewing capability. This step is not particularly exciting, but can serve to draw users into extended use. Use can
be extended further by adding the ability to post text from the mobile,
especially for sites targeted at already-texting youth.
The application can get more interesting, and more integrated into
users’ lives, when the camera and microphone are integrated into
the application. Now users can make podcasts, provide pictures, and
provide back to the community not just summaries of events, but
records of events as they happen. A video clip captured at a concert,
child’s soccer game, or in the schoolyard can be shared on YouTube
for the world – or just friends – to view. The tapestry of services available extend current online-only communities into more immediate and
richer interaction, increasing the addictiveness of the services.
2.2.3 Physical and Mobile Hybrids
A new type of community-building service is developing: hybrid
mobile–physical. Technologies such as near-field communications
(Bluetooth, Wi-Fi) and location enable physical interaction, mediated
by the mobile. The types of service provided by these communities
usually have desktop access almost as an afterthought, perhaps just for
signing up and configuring the service.
Geotagging, for example, is the focus of several start-up companies.
The idea is that people can tag, and comment upon, a physical location in much the same way a service like Digg allows users to tag
and comment upon arbitrary Internet stories. Similarly, physical world
GROUPS AND TRIBES 19
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games using location tracking of other users in the game make a giant
playground out of a city.
Some services enable connections to be made with people in the
users’ social or business networks. Some match-making services alert
the user when a person with a compatible profile is nearby; other
models exist. Business networking services are also available. The idea
behind the business networking is simple: enable the ability to obey
the oft-repeated advice, ‘never eat alone’. The user consults with the
service to see who in the network, perhaps a second- or third-degree
connection, is nearby; a quick text message helps decide whether doing
lunch is plausible and desirable. Many social dating services work
similarly, but are more likely to be used in a bar than a conference hall.
2.2.4 Mobiles as Status
For most of their existence, mobile phones have provided some sort
of presumed and visible status to their bearers. They started as indications of the bearer’s importance or perhaps wealth. As they became
smaller and less expensive, the presumption of wealth declined, but the
presumption of importance remained.
Ring tones can also provide status. The default Nokia ringer is
perhaps as well recognized as AOL’s ‘You’ve got mail’ sound. Downloaded ringers provide enormous customization but also an indication
of the user’s personality. The ‘mosquito’ ringer, inaudible to most
adults, provides teenagers the ability to differentiate themselves from
adults – especially teachers.
Mobiles have had impact on the physical appearance and capacity of
heavy users. Some users experience repetitive stress injuries from large
amounts of texting. Many users, particularly youth, have experienced
a shift in dominance of hand muscles, and their thumbs become more
perpendicular to the body of the hand than their parents’ thumbs.
This physical shift in thumbs, and indeed the use of thumbs as the
primary input method, has spawned the term ‘thumb tribe’ or ‘thumb
generation’: perhaps the ultimate status symbol.
As mobiles have become smaller, they have also become fashion
statements. Japanese and Korean youth wear phones on necklaces.
Nokia has long provided decorated face plates. Motorola, with its
RAZR and StarTAC, is good at creating fashionable devices for the
tech and business crowds. Some high-end carriers promise a new phone
every two months. Nokia has created the solid gold phone, for tens of
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thousands of dollars; they will indeed replace the innards of the phone
as technology demands.
2.3 INTERNATIONAL DIFFERENCES
A common mistake is to assume that the mobile environment in one’s
home country is replicated internationally. This assumption is not only
wrong, but it can lead to very costly mistakes. Differences include
mobile industry structure, pre-existing telecommunications environment, and cultural differences. These combine to create different expectations and success conditions for applications and services.
Japan’s iMode has been a major success for NTT DoCoMo, the
Japanese carrier, while the competing Wireless Markup Language
(WML) has largely been a failure.5American carrier executives visited
Japan to understand the business and technology and proceeded to
implement similar business models on their home turf. Perhaps the
biggest error was marketing these Internet-based mobile sites as ‘The
Internet in the palm of your hand!’. Americans, who have prolific access
to computers, phones, and Internet access, did not believe that they
would have a good experience on a text-only 10–20 Kb/s connection
with a text-only phone. Europeans felt the same, especially since they
had a successful text messaging
still affects how people view the mobile Internet.
On a lighter note, European bloggers have written ‘how to’ lists
targeted at US consumers intended to encourage Americans to rely on
their mobile phones more. The key recommendations include leaving
the phones on all the time, carrying the phones all the time, and
giving out the mobile phone number as the primary phone number –
all things European mobile users do as a matter of course. These
recommendations were written assuming that the calling party pays for
the call – but in the US mobile phone calls are charged to the mobile
phone owner regardless of whether they are incoming or outgoing. The
recommendations were useless in the US environment since American
6
environment. This marketing error
4
4
This is commonly referred to as WAP, or Wireless Application Protocol. In this book we
will refer to the markup language rather than the access protocol, to maintain consistency
with the desktop Internet. After all, web sites are HTML sites, not HTTP sites.
5
Both WML and iMode’s cHTML (Compact HTML) have been superseded by XHTML
Basic. Some devices have WML and cHTML extensions that thereby constitute XHTML
Mobile Profile.
6
Technically known as SMS, or Short Message Service. This is a store-and-forward text
messaging service for short (usually up to 160 characters) messages.
INTERNATIONAL DIFFERENCES 21
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users would not want to pay for the experience of having a telemarketer
or stranger call their mobile.
Not only are the users and their contexts different, the industry
itself varies significantly between regions, particularly in the relationships between carriers, device manufacturers, and content providers.
In Europe, expect the device manufacturers to have the majority of the
power.
2.3.1 Europe
Perhaps due to Europe’s recent history developing a cross-national,
consensus-based government, European industry tends to avoid
jumping to market with the latest technology. Companies instead
collaborate and develop standardized technologies that all companies
can share. The manner in which telecommunication standards and
policy are created and implemented supports this. The development
of digital GSM (Global System for Mobile) in the 1980s in Northern
Europe, rather than adopting analogue mobile technologies, was due
to this consensus building process.
A key feature of the GSM system is the Subscriber Identity Module
on the inserted smartcard, or SIM card. It stores user and billing information, including mobile operator and phone number, so that a user
can theoretically use any GSM phone with a single account. Mobile
operators do not have to manage phones as much as they have to
manage SIM cards. Without such a card in the phone, the phone will
not work.
The uniform GSM system allowed mobile phone manufacturers to
create a single phone that would work for all European and other
GSM carriers, instead of having to target phones at different carriers.
Further, users could take a phone designed for one carrier and use it
with another carrier. This meant that consumers could freely choose
between devices, independent of their decision in choice of wireless
operator. Further, phone manufacturers could spend engineering and
design effort focusing on features rather than on carrier requirement
compliance.
It also meant that the carriers were able to create near-universal,
redundant, cell coverage, especially compared to American digital
coverage. Thus they could compete neither on coverage nor handset
selection. This advantageous environment for device manufacturers is
likely what has given them most of the control in deciding what devices
get designed and shipped in Europe.
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Social Factors
The key factor to remember about Europe is that it is not one culture
but many. Expecting a Swede to behave as a Greek will leave you with
an application one group or the other may not use. British passersby will probably pretend to not see or hear a person chatting on the
phone, but the French are less likely to feign ignorance. Be sure to
design for all the markets you are targeting, not just the one sharing
your corporate language.
The major social factor in the development of the current mobile
telecommunications environment was the existing landline telecommunications environment.
Telecommunications Environment
Much of Europe has had expensive landline phone access. Phone calls
can be costly. Internet access, even in 2003, was typically found only
in work environments. Phone bills might not be itemized and thus
not predictable, leading some people to avoid using the phone at all.
Protected monopolies eliminated any need for incumbents to change.
European operators made a pair of decisions different from US operators that have had far-reaching effects – calling party pays and cheap
SMS. Whereas US operators charged the mobile users for receiving a
call, European operators put the cost of mobile termination on the
shoulders of the calling party. This required a separate numbering
scheme for mobiles to ensure the calling party knows of the incremental charges, but encouraged users to leave the phone on and take
calls.
Since the European operators were not expecting SMS to make
money, they priced the service inexpensively. SMS was the cheapest
way to send a message of any flavor to another person, and it was
always available from the phone. Its convenience and price made
the service very popular. It was powerful due to the standardization of mobile services: SMS worked across carriers. When American operators saw how popular the service was – despite the cheap
American access to the Internet and email – they priced SMS at five
to ten cents per message for something the user could get for free
elsewhere.
Mobile telecommunications provided other advantages compared
with landline telecommunications companies (telcos). Some opera-
INTERNATIONAL DIFFERENCES 23
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tors itemized bills, introducing some competition. Equipment was
generally less regulated. And, of course, the mobile was carried with
the user.
All this has combined to make mobile penetration quite high –
over 100% in Italy, Sweden, and the UK in 2004. Analysys Research
expects mobile penetration for all of Western Europe to reach
100% in 2007.
Mobile Data Usage
While mobile penetration is high, data usage varies. SMS, though sometimes not considered as part of data, enjoys significant success. Web
browsing and MMS has not been as popular. SMS popularity has
derived from several factors:
•
low cost of sending a text message compared with making a voice
call or accessing the Internet via landline
•
sending party pays encourages people to subscribe, since they can
easily control their costs
•
carrier interoperability means that users can send messages to people
on any network (US carriers did not have interoperability until 2000
or so).
Web browsing, multimedia messaging services, mobile video, and
similar services have not had similar success. This has been due to:
•
marketing missteps – asserting that it is ‘The Internet in the palm of
your hand’ or, more recently, ‘Television on your mobile’ is patently
absurd because both services had significantly less choice than their
full-sized counterparts and a much worse user experience with both
screen size and quality
•
lack of usability – difficulty in setting up a mobile for Internet access,
browsers that automatically exited when connectivity dropped,
browsers that then returned the user to the home page when
restarting, and very difficult to use applications
•
lack of consideration for mobile as having different needs – for
example, replicating desktop browser behavior on mobiles such as
returning to the home page upon starting the browser causing any
interruption to abort the user’s task
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•
lack of interoperability – while SMS works largely the same across
devices, MMS, video, and web all have cross-device rendering issues,
making it more difficult to provide content to everybody
•
operator push for a ‘walled garden’, providing access solely to the
applications approved by the operator
•
lack of a compelling business model to make the creation of
compelling services worthwhile.
2.3.2 Japan
After World War II, Japanese business has been dominated by clusters
of trans-industry corporations with close working relationships. Each
cluster is called a ‘keiretsu’ and typically includes at least one bank.
Corporations in a keiretsu have preferential or even exclusive rights to
provide services to one another.
The Japanese mobile phone is the ‘ketai’, and the best way to
research devices, carriers, platforms, and the industry is to use that
word. Mailing lists discuss ketai to the exclusion of mobile phones in
other parts of the world, and the Japanese are proud of their global
technology and industry leadership.
Social Factors
Japanese living conditions, especially for youth, are crowded and
expensive. Landline phones are shared. Computers are shared. Youth
often stay with their parents for years. Thus the ketai is the first
personal (individual) method of communications a young person has.
Relationships are very important in Japanese culture, so tools
that facilitate communication have a receptive market. Some iMode
applications created virtual girlfriends, which would be happy, sad,
demanding, or needy based on whether the user communicated with
her, sent her virtual flowers, or performed other virtual relationship
maintenance tasks. Thus it is no surprise that iMode’s email offerings
constitute the vast majority of iMode use, especially since the company
does not have SMS.
The Japanese tend to have the most features on their handsets, and
they tend to use them. An infoPLANT survey
7
Translated and summarized by What Japan Thinks, at http://whatjapanthinks.com/2006/
01/19/mobiles-are-alarm-clocks-cameras-and-calculators/
7
in late 2005 found
INTERNATIONAL DIFFERENCES 25
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that, in addition to voice calls and mail, at least half of users also
regularly use:
•
alarm (85%) – a later survey found that 43% of Japanese users
actually use this to wake up every morning
•
still camera (83%)
•
MIDI ring tones (82%)
•
calculator (80%)
•
games (66%)
•
optical code reader (54%)
•
high-fidelity ring tones (MP3 and similar) and videos (51%)
•
calendar (51%).
Other items in the list included video cameras, remote control, music,
and electronic wallet. Perhaps more interesting was the last item: ‘None
of the above’, as only 0.3% of users selected this. That means that
99.7% of users used features beyond mail and voice, even if the services
did not require connectivity.
Telecommunications Environment
The Japanese mobile industry functions as a keiretsu, to the point that
Richard Meyer, in hisJ@panIncarticle, called it a ‘keitairetsu’. Although
not as formal as earlier keiretsu, it is dominated by the operator NTT
DoCoMo but also includes such industry giants as NEC, Sony, and
Matsushita (which includes Panasonic). The result is that DoCoMo sets
the technological and service trend for the entire ketai industry.
In contrast with the European industry, the top tier ketairetsu players
provide detailed device specifications and have historically developed
their own standards. Lower tier players, which include foreign companies, may see the specifications after the first devices have gone to
market. DoCoMo introduced iMode, for example, in 1999 using a
proprietary version of HTML targeted at mobile devices.
This has started to change, with ketairetsu involvement in standards bodies such as the Open Mobile Alliance. However, the
Japanese are likely to implement proposed standards long before
they are formalized, making the ketai implementation vary from the
standard.
This industry structure allows NTT DoCoMo, in particular, to create
services that require deep handset integration. Japanese companies
were the first to launch services like mobile wallet and video phone.
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Mobile Data Usage
Wireless industry executives have made pilgrimages to Japan to understand why iMode and ketai in general is so popular. They have focused
on the technology and on the services, a few have looked at the price.
They have missed the social factors listed above, the integrated design
of the handsets, and the fact that the majority of Japanese wireless data
usage is messaging. The executives failed to notice the entire iMode
ecosystem and have thus failed to replicate the success elsewhere.
Japanese mobile data usage is high, but only 20% of customers used
their phone for more than just voice and text messaging in DoCoMo’s
8
fiscal year 2004.
The iMode ecosystem, with its many services, do
not lure everybody into using horoscopes, shopping lists, and dating
services. Mobile wallet use sits below 10% as of 2006.
As 3G handsets became more stable and less expensive, adoption
is increasing. NTT DoCoMo is not making great conversion to the
new services, but KDDI has a very high conversion rate. The Japanese
handsets are more advanced than their European and American counterparts, and advanced features are starting to be used.
2.3.3 United States
The United States is generally considered to lag Europe, Japan, and
Korea. This lagging is ascribed to a combination of ineffective companies and a less educated market. Certainly mobile phone penetration
is lower, text messaging is less popular and lags European use, but
this is changing. Regardless, the size and affluence of the market as
well as the entrepreneurial environment mean that the country must
be considered.
Social Factors
American teenagers are accustomed to having their own room, perhaps
their own car, and frequently their own phone line and phone number.
Computers and cheap Internet access are common, particularly among
those who might use a mobile phone for data access. Local phone
calls are free. Email is not quite ubiquitous, but certainly normal.
8
Note that the services listed earlier were from a survey accessed by a link on the iMode
home page that was present for two days, so the results are skewed towards frequent users.
INTERNATIONAL DIFFERENCES 27
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GameBoys, televisions, and a constant barrage of media are typical for
the American teenager.
In the 1980s and early 1990s, workers who needed always-available
access, including doctors and repair technicians, generally used pagers.
An entire pager shorthand evolved, with people able to send sophisticated short messages using only digits. Text pagers made this communication more robust but did not take over the market, coming late to
the game. Pagers were so popular that, even when mobile phones had
both text and numeric paging available, pagers remained a typical part
of the worker’s belt load.
The mobile phone represents yet another way to connect to others,
and more expensive than either landline voice calls or email. The need
just wasn’t as high as it was in Japan and Europe.
Telecommunications Environment
In the 1990s, Americans enjoyed unlimited local phone calls, including
dial-up access for the Internet, for a flat rate. Local access might cost
around $25 per month; Internet might cost another $20. Even longdistance calls had dropped to pennies per minute. The calling party
paid for calls. Teenagers spent hours chatting on the phone; computers
were set to automatically redial to the Internet provider whenever the
connection was dropped.
American wireless carriers selected different technologies, including
analogue (AMPS), CDMA, GSM, and TDMA. They created systems
that could make voice calls to each other, but that was the limit of the
interoperability. Text messaging was not interoperable: in fact, many
US carriers supported mobile termination only. Users could not send
a text message from their phone, or if they could, it could only go to
phones using the same carrier.
Paging networks had become popular. Inexpensive paging service
sent a phone number only, and advanced services sent text messages.
Some pages could even reply to messages, although most presumed
the message would be returned by a voice call. Pagers had become
integrated into many types of professions, including technical support
and doctors.
Within this environment, paying an additional $40 per month for
a mobile was expensive. Paying for incoming calls required a shift in
mindset, and made people unwilling to give out their mobile number.
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Mobile numbers are considered quite private, and many people will
refuse to call a mobile if the landline number is available.
Compared with unlimited free email, ten cents for a text message is
expensive, especially when many people cannot receive text messages.
It took some time even after the carriers achieved SMS interoperability
and mobile origination before a lot of people signed on. Messaging
plans start at around $3 per month but can run up to $20.
Mobile Data Usage
US data use, like Japan’s, should be separated into messaging and
other use. The success of messaging-focused devices like the BlackBerry
and the Danger’s Sidekick suggest that there is a robust market for
messaging services, but they should integrate into the well entrenched
email and instant messaging ecosystem.
Americans, like Europeans and Japanese, like ring tones and other
methods of customization. All also like games. The top mobile games
in the US tend to match the top mobile games in the UK. The US
market lags a little in penetration rates, likely due to:
•
all the issues described in the earlier European section
•
inexpensive Internet access on computers reducing the differential
value of mobile access
•
the computer-based advertising market, both email and Internet,
being effective enough that mobile investment was not worthwhile
•
service interoperability being harder than in Europe due to different
standards.
Of course, these reasons feed each other: people were on the desktopbased Internet so content providers focused there; because content was
on the desktop-based Internet people didn’t move elsewhere.
2.3.4 Other Regions
Other parts of the world share characteristics with one of the three big
markets listed above. Large parts of Latin America use GSM; China
and India have adopted more of an American model of part CDMA
and part GSM. Indian mobile phones are expected to have a Nokialike user interface, whereas Chinese phones vary as much as Japanese
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phones do. The Korean market and users have as much sophistication
as the Japanese market, with a similar industry structure.
If targeting one of these regions, you’ll want to research your user
base carefully. Different cultures have different behaviors and expectations of their mobile devices, and can interact with their technology
very differently.
One dimension of variability is simply the degree to which users
are likely to read the user guide. User research performed by many
transnational product companies has indicated that many Americans
never open the user manual, Italians are likely to toss it out with the
packaging, and Germans are likely to read the entire thing before using
the product. Similarly, Indian users are likely to read everything in the
box, including the manual. A Chinese user, on the other hand, may lose
face if caught reading the manual. Behavior varies across the world as
well as from person to person.
These cultural differences are made clear by two differences of
opinion I had with developers. One set of Korean developers thought I
must surely be mistaken by insisting that names should be arranged by
last name, and last name should be listed first by default for an American audience – they thought that certainly the ‘first name’ would be
first. Another set of Indian developers argued that a particular button
could readily control three modes of text input. After all, it was clear
enough when you read about it in the manual. They were completely
floored when I told them that just a small faction of their American
users would even open the manual, and we adopted the simpler design.
In short, a bit of background research will give you a lot of information about historical factors affecting your target markets, and can
suggest where user research will be most needed.
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Mobile Devices
The current mobile device market has ill-defined and irrelevant market
segments. There is an artificial distinction between ‘phone’, ‘smart
phone’, and ‘PDA’. This distinction appears to be based on the evolution of the device types rather than actual market segmentation.
Most industry analysts define ‘PDA’ as ‘a handheld device with
downloadable programs operated with a stylus but with no voice
communications abilities’, and a ‘smart phone’ as ‘a mobile phone with
advanced capabilities’. In standard industry practice, a PDA is a smart
phone without voice capabilities. It’s no wonder that PDA numbers
are plummeting. Then again, a ‘smart phone’ is distinguished from a
‘phone’ by having advanced capabilities; this definition results in an
unstable set of features.
The problem is exacerbated by Microsoft’s branding of devices using
their phone operating system as ‘Smartphone’. I have seen reports
that Microsoft coined the term, but the term actually long predates
Microsoft’s entry into the market. Many companies have defined
‘feature phone’ to mean a phone with data capabilities (as compared
to a voice- and text-only phone) – the industry as a whole is likely to
define feature phones as smart phones.
Clearly a better understanding of the mobile market is necessary.
3.1 A DEVICE TAXONOMY
Previously, we discussed characteristics of mobile users: interruptible, easily distracted, sociable, available, identifiable, and immersed in
Designing the Mobile User Experience Barbara Ballard
© 2007 John Wiley & Sons, Ltd
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their environment. Regardless of these commonalities, their needs and
interests vary immensely.
These interests and needs affect users’ choices in devices. An emailcentric user might want a RIM BlackBerry or a Palm Treo, devices
that have rich information services and interface but a less than ideal
voice experience. An outside sales representative might live and die by
a voice phone, and would prefer to relegate data services to a less than
ideal experience. A medical doctor might need to see large amounts
of information simultaneously, and could consider that large screen
worth the cost of not being able to fit the device in a shirt pocket. A
student immersed in social networking software would like a device
focused on messaging and the web.
The mobile computing device market will not converge on a single
physical form any more than the automobile market has converged on
a single form. Devices will instead converge on a set of form factors
based on market needs. The devices will fall into four classes:
•
general-purpose work: multi-purpose devices, likely to be near the
user while at work only
•
general-purpose entertainment: multi-purpose devices with an entertainment focus, likely to be near the user when entertainment is
acceptable
•
general-purpose communications and control: multi-purpose, personal devices, used to communicate using voice and text as well as
control things like home automation or finances
•
targeted: devices intended for one or a very small number of tasks,
with forms varying with their purpose.
Targeted devices are intended to do a very small number of tasks
very well, and are available to the user in correspondingly more limited
contexts. Such devices might be always present if they can become
largely environmental: a wrist watch or an iPod can essentially be worn
and forgotten; a clock is hung on the wall and does not require any
sort of attention except when somebody needs to know the time.
User needs drive more than just feature sets, they also drive design
decisions such as input method. A low-end phone works well with
a scroll-and-select interface whereas a high-end phone might have a
stylus interface. A device’s primary purpose will affect its form; a game
device, for example, is likely to be wider than tall and have several
specialized game buttons. Different characteristics drive how the device
is used and how best to design for a particular device.
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3.1.1 General-Purpose Devices
General-purpose devices are intended to take full care of a specific
market’s needs. These devices are likely to be used frequently within
their domain: work, entertainment, communications.
Since they have to support several functions, these devices will tend
to coalesce into predictable computer-like forms: text input, cursor
control, and a screen. The exact mix varies with device type. In
contrast, targeted devices have fewer form restrictions and can instead
be designed to perfectly match the tasks they support.
Work
Many, if not most, modern workers use some sort of computing device
while working. While targeted devices include cash registers, inventory scanners, and ticket takers, the most common general-purpose
computing device for work is likely the personal computer. However,
the PC may not remain as ubiquitous as new mobile forms become
available.
Computer manufacturers will continue to dominate the generalpurpose work device market, with devices running operating systems
similar to those on modern PCs. A more mobile device might have a
tablet form, with a keyboard available but not required and multi-point
touch or gestural input. It might have multiple screens, detachable from
the device. It might readily connect with various environmental displays,
ranging from projections and wall displays to private desk displays.
Because these are general-purpose work devices, they need to support
screens large enough to view documents, forms, and the like. As
a result, these devices will remain fairly large, with the size of the
keyboard and screen limiting miniaturization. Even a foldable display
will require space to use. For now, these devices are basically laptops
or tablet computers with available operating systems.
While the decades-old promise of useful speech recognition has not
yet been realized, its realization will not render keyboards obsolete.
Speech recognition is useful for predictable text entry and commands.
It will be best used in word processing situations and limited command
set situations. It will not be particularly useful for changing labels for
layers in Adobe PhotoShop, typing math functions, or precise character
entry. It could potentially be useful for spreadsheet use, as long as
there is a good method for error catching and correction. There may
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therefore be some sets of information workers who do not need a
keyboard, but they will be in the minority.
Truly mobile workers have many of the same characteristics and
challenges as the users described in this book. A delivery driver or
meter reader might be interrupted by a person on the street. A sales
person charged with tracking her company’s inventory at stores will use
her work device in a very sociable and readily distracted environment.
General-purpose work devices, however, will tend to have operating
systems based on full desktop operating systems; many of the deviceimposed limitations will not apply.
Entertainment
General-purpose entertainment devices will have a cluster of entertainment features, based on market segment. One device might be mediabased, with video and music prominently displayed. Another device
might be game-based, with music and video as a secondary feature. A
third device might be based on the written word, allowing the user to
work pencil puzzles, read e-books, and browse the Internet.
While an entertainment device might be focused, it will still have
add-on features. A multimedia device, focused on music and video,
may have a book reader as an add-on feature. The written word device,
focusing on ebooks, may have a music player and messaging, but likely
not video.
The difference between a ‘primary’ and an ‘add-on’ feature is
evidenced in the primary user interface of a device as well as the industrial design. Devices focused on voice communications have an obvious
speaker, a numeric keypad, and a microphone; when numbers are
typed at the standby screen, it assumes you are attempting a voice call.
Devices focused on games will have game controllers as their physical
inputs. On either of these devices, access to a web browser might be on
a special button, but is more likely accessed through a menu system.
Add-on features are less easy to use due to the need to make the
primary features easier. Any device that attempts to make all features
equally easy to use will discover that the entire device is difficult to use.
Communications and Control: the PCD
When considering various communications technologies, it becomes
clear that in industrialized societies, everybody has access to a
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communications device. Some people have a simple telephone, either
landline or wireless. Others have communications access using voice
over Internet protocol (VoIP) from a computer, specialized phone, or
even mobile phone. Regardless of the form, communications devices
are an increasingly important part of the lives of most people.
A communications device is a device whose primary purpose is
communications. Certainly a personal computer is used to communicate, but communications can be considered a secondary purpose
to general computing. Given that many people use their computers
primarily for web surfing, email, and instant messaging, it becomes
clear that some full-sized computers are communications devices.
The mobile communications device has a special role. It represents
a person’s always-available connection to the virtual world, both to
information and to people. The importance of this connection was
represented in the past by the prevalence of public telephones, which
allowed connection to others while away from home.
The mobile communications device is so important, both to users
and to mobile industry professionals, that we have given it a specific
name: personal communications device, or PCD (see Figure 3.1).
A PCD is a mobile communications and control device. It is distinguished from other devices, particularly from full-sized computers, by
being:
•
Personal. The device generally belongs to one person, who will carry
it either full-time or for a significant portion of time. This provides an
‘always with you’ experience that personal computers cannot match.
•
Communicative. The device sends and receives messages. Currently,
most PCDs use text messaging (Short Message Service, or SMS) and
perhaps other messaging standards (such as Multimedia Messaging
Service, or MMS) layered on top. This may not always be the case.
•
Handheld. The device can readily be put in a pocket, worn on a
waistband, or in rare cases strapped around the neck. Note that
nestling a device such as a Tablet PC in the crook of one arm and
then operating it with the other arm is not ‘handheld’, it is instead
arm held and requires both hands.
•
Wakable. The device can be awakened at a single touch by either the
user or the network. A mobile phone will receive a text message even
when it is ‘asleep’, or in standby state. Note that most computers,
if they are asleep, cannot communicate with the network. This
allows an ‘always on’ experience that personal computers cannot
match.
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Figure 3.1 PCD characteristics
A communications and control device is almost always a mobile
device. While desktop phones certainly could perform many of the
activities mobile phones do, the user experience cost of doing so is too
high compared to the value obtained. It is far easier to use desktop
phones as targeted devices and move the remainder of the communications and control functions to the computer, which is likely sitting
next to the phone and has better display and input capabilities.
3.1.2 Targeted Devices: the Information Appliance
Targeted devices are designed to help the user do a small number of
tasks, and to do them well. Their form is thus highly variable and
targeted at the exact device purpose. These devices include cameras,
watches, televisions, radios, music players, credit card machines, automatic teller machines, and bar code scanners.
The functions targeted by these devices are frequently included in
other devices. For example, most people have several clocks, and
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several more devices that include a clock as part of the function. Clocks
are included in most computers, kitchen appliances, and car stereos, as
well as being their own separate devices. Cameras are found in security
systems, computers, and mobile phones, as well as in the hands of
photographers and tourists worldwide. Users will tend to have multiple
instances of the functions supported by a targeted device.
A targeted device is also known as an ‘information appliance’, a
1
term coined by Jef Raskin
to mean a device designed to do a small
set of information-focused tasks very well and be closely matched to
the needs of the people using them. Raskin notes that these devices
tend to be simple, always deal with information, and tend to share
information.
Because the targeted device’s simplicity of function, it cannot by itself
provide the necessary ecosystem to support non-trivial data. A music
device needs data to play. A camera is useless without a way to share
or print pictures. An ATM is a sure route to bankruptcy without its
connection to the bank’s network. Thus all but the most trivial devices
are part of an information ecosystem, and their data is shared with
other devices and systems. Thus a typical characteristic of a targeted
device is the need for reliable methods of data transfer. If it uses only
proprietary data transfer methods it ties the user into a very small
network, which could reduce the marketability or the usefulness of the
device.
Given the likelihood that the user is already carrying a multipurpose
device, there is little benefit to making a targeted device have lots of
features. Any features that are not in the target set are going to be more
difficult to use, or could possibly worsen the overall user experience.
Features must be added to a targeted device with caution. Leave the
job of a multi-function device to a device designed from the beginning
to be a multi-function device. In other words, don’t ask your watch to
manage your investments.
One issue with targeted devices is the fact that developers frequently
want to add on features. These add-on features can inhibit the overall
user experience if not done carefully. For example, Apple added on a
calendar view in its iPod. The existence of this feature simply uses the
existing data connection with a computer and screen. This addition
1
Donald Norman popularized the term in The Invisible Computer: Why Good Products Can
Fail, the Personal Computer Is So Complex and Information Appliances Are the Solution,
1998, MIT Press (Cambridge, MA).
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does not inhibit the use of the main function of the device: listening to
music and other audio content.
Had Apple instead tried to add event entry into the calendar, at
best event entry would not have been used much. The worst scenario
would have been if Apple had decided to build a text input function
to support add-on functions, which would have adversely affected the
user experience for music.
Third-party developers are perhaps most notorious for demanding
and building these add-on features, making the device into something
it was not intended to be. These developers can have a disparately
strong voice in product design, since device manufacturers understand
that developers build device sales.
Targeted devices have fewer size issues than general-purpose mobile
devices. The screen, if present, needs to be only as large as its data
demands. Input mechanisms can be limited to only that which the target
device demands, and need not be sized to support general-purpose text
input. The shrinking size of music-only iPods, progressing to the size
of a stick of gum, illustrates that screen size need not dominate the
design.
Applications written for information appliances need to be written
for the specific device or device family being targeted. This does not
mean that some devices will not have general-purpose platforms such as
Java ME or Linux, but instead that there may be significant customization of the platform. For example, MIDP 1 applications ran on BlackBerry devices, but could not use the device’s navigation mechanism.
To make a good MIDP application for BlackBerry, RIM’s extensions
must be used.
Historical
Abacuses and clocks are perhaps the earliest information appliances,
storing changing information outside the brain. More recent examples
include calculators, standalone word processors, cameras, and audio
equipment. Most of these have evolved without the ability to share
data with other devices, requiring paper or human to shift about data.
They are therefore not stellar examples of information appliances, but
are indeed targeted devices.
What we should learn from these devices is the enduring value
some of them provided to society. Information tools changed navigation techniques, facilitated commerce, helped record history. All but
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one of the examples listed above remain in widespread use; even the
mechanical abacus is still used in markets across parts of Asia. In
contrast, the standalone word processor is not used much today, but a
computer running a word processor looks so much like a standalone
word processor that perhaps there is little need for a separate device.
Current
There is a broad array of targeted devices currently in the market.
Targeted work devices, for example, are designed to support a set
of similar job. Symbol Technologies designs devices surrounding
inventory control, with extreme ruggedness and built-in scanners.
Manufacturing processes are becoming more accessible to smaller
organizations, with contract manufacturers willing to do an entire run
of less than 10 000 units. This fact is leading to smaller and smaller
companies being able to create truly custom devices. An early example
of this phenomenon is the UPS Diad computer for UPS package delivery
drivers, shown in Figures 3.2 and 3.3 and designed and built by Symbol
Technologies.
This device has been so successful that UPS continually updates the
design. The company has a separate device for warehouse package
handlers, the ring scan. Note that the warehouse device apparently has
less need for text entry, as there is a phone dial pad type of letter-tonumber mapping on the warehouse device where the driver device has
extra keys to support easier letter entry.
A more common information appliance is the iPod music player.
Audio-only iPods do one thing well, and have a small number of extra
features available. Video iPods, on the other hand, are more properly
general-purpose entertainment devices.
Digital cameras are becoming pervasive as well. Like music players,
cameras represent a function that could be, and often is, integrated
into a multipurpose device. Nevertheless, the standalone devices still
sell well. This is because the targeted devices provide a quality of
experience and ease of use that cannot be matched by the necessary
subsumption of feature access and use when it is included in a generalpurpose device. A camera might need to be turned on, but once it is on
pictures can be taken with a single key press. On a phone, the camera is
accessible at best with a camera button, then the application is loaded,
a picture can be taken, then menus are used to decide what to do with
the picture.
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Figure 3.2 UPS Diad IV targeted work device for drivers. Image downloaded
from http://pressroom.ups.com
3.1.3 Ubiquitous Computing
Computing has expanded well beyond the terminal and mainframe
model of the 1970s. The personal computer started the revolution of
decentralizing data and some large portion of application functionality.
Mobile devices extend this further, with connections both to personal
computers and to servers. A complement to mobile computing is ubiquitous computing.
Ubiquitous computing is computing embedded in the user’s environment. It is distinguished from ‘computers’ in that the devices
are not personal computers, regardless of the hardware. Computing
devices and displays recede into the environment, becoming invisible.
Proponents sometimes call ubiquitous computing ‘calm computing’, as
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contrasted with desktop computers which actively demand the user’s
attention.
Ambient Devices makes devices geared towards information ‘glanceability’, much like wall clocks. Their devices display information such
as weather, stock prices, and so forth in an abstracted manner using
physical devices. For example, the Ambient Umbrella pulses blue if rain
is forecast for the day. Users of the ‘dashboard’, as seen in Figure 3.4,
can subscribe to a large number of information feeds, including corporate data, and get information based on three analogue meters. The
angle capitalizes on the eye’s ability to quickly distinguish angles,
particularly distinguishing vertical from other angles.
Various public information points can be considered to be early-stage
ubiquitous computing, although the screen paradigm is still heavily
embedded. These include ATMs, flight status displays, and kiosks.
Note the similarity in scope of the targeted devices described above.
The chief difference is that they are built from computers rather than
from custom hardware.
Public information points are evolving to include services that
directly interact with mobile devices via near-field communications
or the Internet. Phone-pay vending machines and mobile-initiated
printing have seen commercial deployment, certain applications can
Figure 3.3 UPS Diad targeted work device for warehouse workers. Image downloaded from http://pressroom.ups.com
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Figure 3.4 Ambient Devices’ dashboard provides glanceable information
in the environment without a computer. Image downloaded from http://
www.ambientdevices.com/cat/gallery.html
be environmentally downloaded to mobile, and more general-purpose
services are being developed in academic research laboratories.
Four major types of ubiquitous computing likely will be highly relevant to the mobile device ecosystem: pico nets, home servers, shared
displays, and public interaction and download points.
Pico Nets
As users have more and more devices on their person, the need for
sharing information amongst them becomes more important. The
Bluetooth wireless technology was created to address this need, and
infrared ‘beaming’ has been used in Palm and Windows CE devices for
years.
The concept of a pico net, sometimes known as a personal area
network, is the idea that all of a person’s devices can share data with
each other, automatically and wirelessly. Bluetooth was designed, for
example, to support both wireless headsets and wider area network
connection sharing. This vision has been slow to come to fruition
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largely due to carriers’ hesitancy to open their networks to the
resulting increase in use, which is a risk both to network integrity
and profit.
However, pico nets of the future will share all sorts of data seamlessly, not just connectivity. One device that has only marginal use of a
data store, such as an address book, might add access to that data store
when it is available on the pico net. Thus a GPS device could quickly
give directions to way points entered on the PCD, without major user
input.
Home Servers
Home servers, such as Apple’s Mac Mini and Microsoft’s Media Center
PC, will become more important. Home servers store videos, music,
pictures, and data backups, serve content to various parts of the house,
coordinate data between different users, and run home automation
systems such as security cameras. Mobile devices can store subsets of
this content, and can also manage the servers – and hence the home –
remotely.
Future applications include answering the door from the mobile
phone, regardless of whether the user is at home. A delivery driver
knocks on the door, triggering an MMS with a picture of the driver
and perhaps a second picture of the driveway or street sent to the
homeowner’s phone. The homeowner can then initiate a voice over IP
connection to the front door and tell the driver to leave the package.
Shared Displays
A solution to the too-small screen problem is to simply connect the
device to a larger screen. To some extent this is done in conference
rooms with projector displays, but a variety of implementations are
possible. A conference room table or wall could display content directly
from the mobile device. Add a bit of interactivity and group access,
and a sophisticated collaborative application could result.
Phone booths of the future could provide a degree of visual privacy
for a display, allowing users to interact either via voice or keyboard.
Similarly, walls in private homes could display aesthetically pleasing
content until somebody wanted to interact with their device with a
large screen.
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Public Interaction Points
An extension of public displays is more fully featured interaction
points. These could allow the user’s device to pull down data and also
push information back.
One student project suggested using near-field communications to
intelligently display airport location information: as a user approached
a gate information display, a ‘you are here’ indicator unique to the
user is displayed. As the user gets closer, the icon grows larger; as
the user moves right or left the icon follows. The icon contains gate
information and number of minutes until boarding, or some similar
information. This information could simultaneously be pushed to the
mobile device.
3.2 ANATOMY OF THE PCD
Of all the general-purpose devices, the personal communications device
is the most ubiquitous. It is always carried by its owner, which has
several important implications in its design. To make an application
available to as many people as possible, it will need to be delivered on
a personal communications device.
The PCD is personal, communicative, handheld, and wakable. As a
personal device, it is not likely to be shared with others. As a handheld
device, it is small, battery powered, and wireless. As a communications
device, it is usually on and connected. It is turned off only in rare
situations, and connectivity disappears only temporarily.
The PCD is also a general purpose device. It therefore has the four
main components of any general-purpose device: display mechanism,
focus control, text input, and development platform. It has several
other characteristics as well.
3.2.1 The Carry Principle
While users will frequently have their general-purpose work device,
they will not when not at work. In contrast, a PCD is always with the
user. This fact has profound implications on device and service design,
and will be explored further in the Principles chapter.
The fact that a PCD is carried with the user all the time means it
is multi-functional. Users will allow for a certain difficulty of use for
the privilege of having the device readily portable. This is akin to a
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Swiss Army knife: its blades and tools are serviceable, but they are
not appropriate for heavy use. People carry a Swiss Army knife sooner
than a set of knives for its convenience and portability. Similarly, the
PCD provides an array of voice communications, text communications,
house control, applications, etc. It is the most personalized device.
The Carry Principle dictates the characteristics in a successful PCD.
3.2.2 Input Mechanisms
Input mechanisms include a variety of methods for getting data onto
a device. Mechanisms can be categorized into focus (cursor) control,
commands, text or character entry, environmental data entry, and
other-computer data entry or access.
Focus Control
Perhaps the category with the most fundamental impact on application
designis focus control.This is themethod that the device uses to decide the
object to which to direct any user input, and the most common methods
are stylus and scroll-and-select. A stylus is similar to a mouse, but has no
cursor and does not have the ability to access multiple commands without
complex actions like press-and-hold or the very difficult double-tap.
A scroll-and-select mechanism has up and down and usually left
and right controls and a select button. While many devices use a ‘fiveway rocker’ with each of the above controls, others use a ‘jog dial’ or
other physical mechanisms. Scroll-and-select works rather like tab and
shift-tab on a computer, with some acceleration of navigation available
in certain situations. Some phones also support a scroll control for
screen-by-screen movement, usually via the volume keys.
Other focus controls are possible. Accelerometers can navigate
through a series of pictures with a wrist gesture or perform other
actions. Speech can select an object on the screen, although this is
fraught with user experience and technical problems. Focus can also
be controlled using keyboard shortcuts, such as numbered list items.
Commands
A more subtle mechanism category is commands, the various methods
beyond select and activate the device uses to perform actions. Hardware
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buttons to activate programs, such as a camera button, are the key
example. Some phones also have a Back or CLR key, which is used for
both aiding character entry and navigation between pages.
Softkeys are on-screen buttons that can be quickly accessed by
unlabeled hardware buttons. They provide context-sensitive commands
in a hybrid of software and hardware button. Devices vary in how
they implement softkeys, and different platforms have varying access
to softkeys. Devices may use, among many options:
•
Nokia-style Options/Back softkeys. Any contextual controls are in
a menu launched by the Options button. Back becomes Cancel in
certain contexts. These phones do not have separate back buttons.
•
Simple softkeys, with two or three virtual buttons and the corresponding number of hardware buttons. The virtual buttons have
labels indicating what actions the hardware button will initiate.
Some phones have separate select buttons, others do not. Either type
of phone may have parts of the user interface in which a softkey is
used as a select button.
•
Samsung-style OK/Menu softkeys. Samsung has used its OK and
Menu hardware buttons to access softkeys. The OK button is also
the device’s select button, so this is essentially a one-softkey design.
•
Scrolling softkeys do not have physical softkey buttons, but instead
have left and right scrolling through a list of actions available for the
currently selected screen or object. The select button always operates
on the action list, never on the object directly.
Third-party software that is burned into the device’s memory may
not follow the conventions found in the remainder of the device.
Browsers in particular are likely to break with the conventions, particularly in their use of softkeys, because the standards have evolved to
drop softkey support.
Speech commands have been present in mobile phones for years, but
they are infrequently used by end users. People consider the feature
when making a purchase but find themselves rarely if ever using it. As
processor capability and amount of content increases, speech recognition will become an increasingly important mechanism for navigating
and acting on content.
Mobile search, both of device content and Internet content, is likely
to be best achieved via speech input, with a combination of natural
language search and robust search results based on all likely uttered
words, not just the most likely. The natural language search increases
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accuracy by giving the recognition engine a predictable grammar, and
the use of multiple possible words for an utterance significantly reduces
the negative impact of misrecognitions.
Text and Character Entry
The input mechanism that has garnered the most attention is text and
character entry. Mobile phones are notorious for having difficult text
entry, although some users gain significant speed. The type of text
entry is partially dependent on the intended use of the device. For
most devices, voice calls need to be dialed using one hand only. This
has limited voice-targeted devices to a standard 12-button keypad,
and its variations. Devices more targeted at messaging can support a
two-handed text entry mechanism.
A one-handed text entry mechanism will not be a keyboard-based
device simply because if the keyboard is shrunk far enough to have all
its keys reachable by a hand holding the device, then the keys become
too small to be operable by a thumb.
The normal one-handed input mechanism is some variant of the
standard 12-button keypad, including ∗ and #. Normally, triple tap
is used to access letters on each key: a ‘r’ requires three presses of
the 7 button. A two-tap mechanism is also possible: a ‘r’ requires a
press of the 7 button, then a press of the 3 button for which letter
it is on the key. This mechanism is slightly faster, but is not widely
adopted.
Recent years have seen a variety of one-handed keyboard alternatives become available. The Fastap keyboard has letters nestled in
between the letters. Accidental activations are avoided by not having
the numbers be buttons at all; instead numbers are activated by
chording the surrounding letter buttons. This chording is invisible to
the user and does not require precision from the user.
Other one-handed text input mechanisms have come on the market.
Some are doomed because they don’t solve the fat-finger problem.
Others use some version of simultaneous button press (chording) to
activate single characters. Gestures of various sorts, such as using a
force stick to ‘write’ letters, are also available. These mechanisms are
likely to stay in niche markets, such as PCDs with very little emphasis
on text input.
Two-handed text input solutions fall into the categories of thumb
keyboards, handwriting recognition, and virtual keyboards. Thumb
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keyboards are found on the BlackBerry and Palm Treo devices, amongst
others, and have buttons operable by people with medium or small
sized fingers. Fingernails can also get in the way.
Handwriting recognition is provided by a number of companies with
varying success. Some users can get very high recognition rates; other
users have a harder time.
Virtual keyboards operated by stylus vary widely. Some are merely
QWERTY layouts, whereas others build in letter and word prediction
with a variable display, but WordLogic uses an intelligent combination
of the two. Users start typing with a standard QWERTY keyboard,
have the most likely next letters highlighted, and have complete words
displayed to the left. Further, a simple gesture function allows users to
build parts of words. A long word frequently is written with two to five
taps. These may be built in to a device, or may have been downloaded
as an additional tool.
Some solutions require not only two hands, but a surface. These
include any full-sized keyboard, whether rigid, rolled, or virtual, as
both hands are used for input and not able to hold the device while
doing so.
Complementing the hardware for many devices are letter or word
prediction programs. A character prediction method is very useful on a
12-button keypad, as it reduces keystrokes by more than half; a version
of the same program can be used to increase accuracy in handwriting
recognition. A word completion program, which is separate from character prediction, suggests words that match the currently entered first
characters. Such programs are useful for even the easiest of mobile text
entry mechanisms.
Some platforms, particularly browsers, do not have access to the
device’s prediction programs. Other platforms have only rudimentary
access: the user turns prediction on or off for the entire platform
at once. For devices in which the application platform has careful
management of prediction programs is necessary, as some fields do
not lend themselves to dictionaries whereas others do. When using the
platform, you may not have access to the prediction programs.
Environmental Data
Access to information beyond the confines of the device is one of
the places where mobile devices are actually more capable than their
desktop counterparts. Cameras, RFID readers, various location tech-
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nologies, thermometers, and any number of other potential input mechanisms gather information from the environment and help understand
user context.
The camera is the most prevalent such input mechanism. Its use
goes beyond taking and sharing photos with friends, and progresses to
bar code recognition and generic image recognition of products, movie
posters, and people. Taking a picture of a menu could add ideas to
your recipe box. A picture of a meal could help you record calorie, fat,
sugar, and carbohydrate consumption.
Expect the camera to be very important in mobile search, with
comparison shopping becoming useful as products similar to the item
pictured are found. Previous versions of comparison shopping looked
only at items with the same model number, and major retailers secured
models with different numbers but the same characteristics. Current
versions, accessible by voice, SMS, on-device application, and web, can
suggest similar products.
Other Computers
Other computers also provide critical data. Servers are obvious, but
ubiquitous computing systems and other devices of the user’s personal
network also provide useful information. A future version of the iPod,
for example, might be connected via Bluetooth to a phone. When the
phone rings, the iPod would pause the music, switch to phone headset
mode, and allow the user to answer the call without changing earpieces.
Such a feature would replicate similar features in an integrated device.
Synchronization, either with the user’s own computers or with a
commercial server, also provides input. There is a growing trend
towards accessing media content, including both music and television,
from the user’s home content library rather than accessing content
directly. This type of input is sometimes known as ‘place-shifting’
when live television from the home is viewed on a mobile device, and
‘time-shifting’ if home-stored content is viewed at different times.
3.2.3 Output Mechanisms
Screens are the most obvious of output mechanisms, with the LCD
as the most common and other technologies in various stages of
productization. While these are the most obvious, the technology actually impacts design of applications.
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The LCD screen will become less and less popular due to power and
cost issues. These screens are rigid, have significant polarization issues,
and require significant backlighting to become visible in sunlight. With
an LCD screen intended to be used outside, all information-laden
graphics need to be high-contrast, with thick lines. Text color must be
high contrast with its background. On the other hand, the polarization
means that the screen is more difficult to see from the side, making
information more secure from casual observers.
The LCD backlighting introduces challenges for the user for applications with low interactivity. The screen will fade after a few seconds
of lack of user inputs. While this is generally a setting that can be
changed by the user, it falls into the category of things rarely found
by the majority of the users. This leaves the user introducing spurious
inputs to keep the screen lit while reading or studying the screen.
2
OLEDs
are made with a radically different manufacturing process.
The OLED pixels emit light directly, giving them better visibility
in sunlight, reduced power consumption, and no polarization issues.
OLEDs have not taken over from LCDs because they have a shorter
life; researchers are addressing the issue. These screens give the designer
a broader range of color choices and allow for more subtlety in design.
3
Electronic paper
contains a smaller ball
displays have a set of balls as pixels. Each ball
4
with two colors; the electric charge tells the
inside ball which color side to display. These displays require low
power to change, and no power to maintain the display. They can only
change approximately four times a second, making them inappropriate
for highly interactive displays. They have almost as good readability as
newspaper. If designing for this type of display, eliminate animations
and reduce screen changes. A clock on the outside of a phone, for
example, should update once a minute.
5
Electrowetting
displays use an electric field to decide whether a
colored oil covers or doesn’t cover the substrate. These displays have
excellent color and low power consumption. Most of the manufacturing process is the same as LCDs, which should allow it to quickly
enjoy economies of scale and have similar costs, but the technology
remains very new. Unlike electronic paper displays, they can also be
changed at video speeds.
2
Universal Displays is a major manufacturer.
3
E-Ink is the primary technology owner.
4
An alternative version of the technology has several balls inside a colored liquid in the
larger ball. The colored liquid provides the color, obscured by the balls at need.
5
Liquavista is the technology owner.
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OLEDs, electrowetting, and electronic paper can be made on
flexible displays and require less backlighting, making them use
less power.
For devices with multiple displays, we expect status displays to be
electronic paper, and video displays to be OLED or electrowetting.
Thus many issues associated with graphic design for mobile phones
will be abated. Glare issues are reduced with electronic paper. Electrowetting and OLED allows for beautiful color with broad angles of
view. All these technologies enjoy lower power consumption, which
will allow for longer use between battery charges.
Various connection technologies such as Bluetooth, Wi-Fi, WiMAX,
and infrared can be considered output methods, but are instead
described under connection characteristics. These connections can send
data to other computers, including the environment, servers, nearby
devices, or other devices within the pico net.
Various speakers can also display data. These include the builtin phone speaker, a speaker phone, and an earpiece. The vibrator,
if present, is also an output mechanism and is accessible by some
application technologies.
3.2.4 Technologies
PCDs support a variety of application technologies, each with different
strengths and weaknesses.
Browsers
Most devices have a browser of some type, provided by Openwave,
Nokia, Access, AU Systems, Opera, or some other provider. This
browser, if found outside of Japan, is likely to support XHTML Basic
or XHTML MP as its primary markup language; a Japanese browser
may support cHTML (compact HTML) instead. All are restricted
versions of standard HTML/XHTML. XHTML browsers will support
CSS whereas cHTML browsers will need styling defined inline.
Some newer browsers also support scripting and even AJAX (Asynchronous Javascript And XML). In general, any prefetching that a web
application can do will improve the application responsiveness and
hence the overall user experience, so these technologies will become
important as they spread.
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Messaging
Devices also have a variety of messaging capabilities. SMS text
messaging is nearly ubiquitous, although it took a few years for US
providers to make it interoperable and two-way. MMS (Multimedia
Messaging Service) allows for the transfer of pictures, text, and sound.
It is hampered by cost and interoperability issues. Mobile blogging
applications may reduce the attractiveness of MMS, but that remains
to be seen.
Voice SMS allows the user to record a voice message and send it
to another mobile user. It is essentially a voicemail message that does
not attempt to reach the user directly first, with the capability to send
messages to groups.
Application Platforms
A device is also likely to have one or more application platforms that
allow development of a local application. These can be divided into
native or targeted platforms, broad availability platforms, and limited
availability platforms.
Java ME is perhaps the most widely deployed of the broad availability platforms. Its creator, Sun, worked towards a ‘write once,
run anywhere’ solution and designed Java ME to be able to run the
same program on devices with different capabilities. As so frequently
happens, the reality did not meet the promise due to poor implementation of the application environment user interface and varying
technology implementation.
Flash Lite will have broader and broader availability, although it
is currently limited. It combines scalable vector graphics (SVG) with
ActionScript, which is based on ECMAScript. Flash Lite allows rapid
development of applications for specific devices, but does not provide
any method of automatically changing application appearance based on
device capability at the device: all optimization must be done by the developer at design time. Adobe’s promise of fast application development
across all devices should be tempered by the reality of device variances,
but the problems will not be as profound as they are with Java ME.
BREW was designed for broad deployment, but is on the Qualcomm
CDMA chipset so is not natively available on GSM devices. There
do exist a few GSM deployments. It is, to the user, similar to Java
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ME except the applications run faster. Deploying a BREW application
requires the carrier to sell it.
uiOne (formerly Trigenix) was designed to allow users to customize
their device’s native user interface. Theoretically this customization
could remove feature access from the device; in practice only the first
level or two of the phone is customized with graphics, animation,
ordering, and sounds. Clearly the operator allowing a uiOne application will want to ensure that all the operator’s money-making ventures
(messaging, voice, browser, etc.) and support needs (settings) are as
usable as they were before the customization.
uiOne now is part of BREW. As BREW is actually a productization
of Qualcomm’s internal development platform for device user interface, this opens up the possibility of some very sophisticated services.
Expect access to such services solely through the operators, so only
organizations with strong carrier ties will be able to take advantage.
Python and OPL (Open Programming Language, formerly Organizer Programming Language) are languages for developing for the
Symbian platform. They are each interpreted, making them slower than
compiled languages such as BREW and C++.
Linux applications can run on an array of devices, but may require
significant recoding for different versions of Linux.
Purely native application environments include Symbian C++,
PalmOS, Linux, and MS eMbedded Visual C++. These are compiled
applications. They have deep access to a device’s capabilities, but
limited cross-device applicability.
Media Players
Media is becoming ever more important. Video distribution has traditionally occurred on mobile devices point-to-point, with a unique
connection between the operator and the individual user. While this
allows for highly customized experiences, it is not bandwidth friendly
and is limited in its scalability. Broadcast solutions will be available
soon, and devices may be able to record segments for local playback
and forwarding.
Person-to-person forwarding of video clips, like pictures, will become
more prevalent. Some mobile marketing firms are in fact counting on
this, and profess expertise in viral marketing. They believe that they can
create advertising content, perhaps embedded in something popular,
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that will be forwarded from person to person without sustained investment from the advertising firm.
Thecentralstandards for media is3GPP(Third Generation Partnership
Project) and 3GPP2 (for CDMA), which define a mobile platform for
MPEG-4 formats. Specific formats include AAC and AMR audio (plus
QCELP for 3GPP2) and MPEG-4 and H.263 video. Content production
tools such as QuickTime Pro readily provide the correct formats.
3.2.5 Connection Characteristics
The PCD is a wireless device. As such, it has:
•
power consumption concerns
•
inconsistent coverage
•
speeds slower than prevalent land line speeds
•
limited coverage area and hence potential roaming charges
•
latency in connection, particularly for establishing the connection.
These characteristics impact application design. For example, an application whose data must be present on the device, such as a calendar
or contacts, should not be a pure browser application. For that and
similar needs, a local application with network access is preferred.
3.2.6 Standby Screen
The standby screen is the main device screen, before the user has interacted with it. It provides valuable real estate for branding, advertising,
and personalization.
User interfaces can be defined to have applications or actions available on the main screen, or applications only available with the press of
a hardware button. Most devices assume that if the user starts typing
numbers, that a voice call is to be made; this leaves the main screen free.
Currently, wallpapers for screen customization are popular and
lucrative. In the future, users may be allowed to have reduced cost of
using the phone in exchange for branding on their main screen.
Application platforms such as uiOne allow for significant customization of the standby screen. Sprint users, for example, can download
themes that have four links on the main page in addition to softkey
links to Contacts and Favorites.
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Selecting Application Technologies
Most business goals can be accomplished by building an application
using a variety of technology combinations. A search application can
be accessed using voice, SMS, MMS (camera and visual search), web,
or an on-device local application. Each of these has different user
experiences, device portability, user coverage, and in general overall
user experience.
While most designers do not get an opportunity to select the technologies that will be used, marketers do, and this is the first decision
that affects the user experience. The ideal scenario, of course, is to get
the content to as many people as possible, with as good a user experience as possible, with as little development as possible. This chapter
provides a framework for making these decisions.
Many of the identified technologies could quite reasonably be on
devices beyond personal communications devices. A digital camera,
for example, could have network connectivity via Bluetooth, Wi-Fi,
or cellular, and a development environment like Java ME MIDP. This
combination would allow direct access to various photo-sharing applications, such as a newspaper photojournalist image submission site,
a photo sharing site like Flickr, or a blogging application. This array
of applications would not be supportable by the camera manufacturer
directly in the software, but an API could make the camera more
attractive to customers once software is available.
Selecting a platform, or combination of platforms, clearly needs to
be done with the full collaboration of your technical staff, who will be
Designing the Mobile User Experience Barbara Ballard
© 2007 John Wiley & Sons, Ltd
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considering a number of factors not mentioned here. This may include
application size limitations (which will vary over time, and thus are not
described here), in-house expertise, technical capabilities, and so forth.
The business members of your team will also consider what platforms
are supported by the desired partner device manufacturers or carriers.
Platforms, and their capabilities, will continue to change. These
changes are usually improvements, but occasionally capabilities are
removed in the name of compatibility. This constant state of change
implies that by the time this book is printed, specific platform data is
likely to have changed; the analysis points raised in this chapter will
remain the same.
4.1 INPUT MODALITIES
The method of input – the phone keypad and focus control – may
seem obvious. There are, however, other options. Most PCDs are
optimized for voice, and voice-over-IP (VoIP) allows the device to
connect to a server using voice, without establishing a separate voice
call. This fact will end up impacting mobile applications profoundly
by allowing voice and sound as data to be transferred over the same
connection as all other data, eliminating the need for a separate voice
call. Cameras are also excellent input devices, allowing for a number
of visual-based applications. Few, if any, applications will be operated
purely by camera.
With the continuing evolution of device capabilities in mind, we
observe that a device can use as input visual, auditory (speech or other
sound), or touch from the environment, much like humans. While
other inputs, such as location and temperature are possible, for most
applications they will not be the primary method of controlling the
application. We thus relegate these to ‘Supplemental Technologies’,
below.
4.1.1 Buttons
Most applications discussed in this book are operated by pressing the
physical buttons on the device, or operating a stylus to press virtual
buttons and capture handwriting. This type of input is extremely
familiar from personal computer applications. While most applications
use buttons for input and control, the phone is designed to be first
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and foremost a voice device, with buttons only to perform necessary
supplemental tasks.
4.1.2 Speech
Speech can be a natural input mechanism for a number of types
of applications. Natural does not, however, mean easy to implement, design, or use. Decades of research and failed products have
proven this.
Challenges associated with speech input include input inaccuracies due to difficult accents, mismatches between spoken speech and
sampling frequencies, and grammar design difficulties. Speech systems
can also leave a user feeling powerless if her utterances are rarely recognized, which can readily happen in mobile phone use environments
due to environmental noise.
Speech also introduces further privacy and politeness issues. Mobile
phone conversations with humans tend to involve a more projected
voice than do in-person conversations with a human in the same environment; this fact has created ongoing resentment against others using
mobile phones in public places. When a user talks with a machine,
they are likely to project their voice even further, suggesting that the
entire train station or coffee shop will know exactly which application
is being used.
4.1.3 Speech+ Buttons
We have speech combined with buttons as a separate input modality
due to both the difference in user behavior if using both speech
and buttons, and the differences in application platforms possible.
Examples of applications using both speech and buttons include voice
response systems like voicemail that ask the user to press a button to
perform an action, and multimodal applications that allow voice to
supplement a mostly visual application.
Voice-over-IP (VoIP) is going to increase the possibility of designing
applications with both speech and buttons. Earlier technologies
required separate connections for voice and data, and one session had
to be ended before another began. As VoIP spreads, speech and data
can be accomplished simultaneously, creating the capability for fully
integrated multimodal applications. Companies such as V-Enable have
been working towards this vision, creating a server environment that
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can recognize speech commands given to an otherwise button-driven
interface.
Using speech as an alternative interface allows users to decide which
input mechanism is right in their current context. If recognition fails,
they can revert to buttons for input.
4.1.4 Visual+ Buttons
The camera is an input device whose importance will increase over
time. It is one of the key methods of inputting environmental data into
the phone. A well-designed application could use the camera to input:
•
a bar code or other visual identifying symbol displayed anywhere in
the environment, allowing for a quick retrieval of specific product
information or marketing interaction
•
an advertisement as a whole, such as a movie poster, for quick
retrieval of product information or marketing interaction
•
a face, both for addition to the user’s phone book but also as a
source for tagging for photo classification
•
a car or even its VIN, to get history of the vehicle before purchasing it
•
a face, to see whether it is in a list such as the sexual predator list,
missing children registry, or simply within one’s social network.
There are numerous uses of a camera. Cameras will not be put in
widespread use as input devices until the devices support the taking of
a picture and then choosing what to do with it, as the amount of time
it takes an application to load is likely going to inhibit any rapid use.
4.2 INTERACTION RESPONSIVENESS
The responsiveness demanded by your users and application should
match what the platform can provide. The fastest response is found in
well-designed compiled applications with memory management being
run directly on the processor rather than in a virtual environment.
1
A simple extension to a platform such as Java ME could be a ‘picture action’, which is a
label and command to be added to the device’s menu of things to do with a picture. This
menu already includes the ability to send the picture to contacts, but could easily include a
command like ‘Find Product’ or ‘Comparison Shop’ or ‘Missing Child?’, each attached to
different applications. Selecting the command would launch the application on the device.
1
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The slowest response is found in messaging applications, which can
best be described as asynchronous. As always, the quality of code
implementation has much to do with responsiveness.
•
Asynchronous applications do sometimes have inherent advantages
over their more interactive counterparts. Their asynchronous nature
allows for user and device interruptibility, as the application itself
is interruptible. Further, the results are stored and displayed locally,
in a predictable location, and the application need not be ‘running’
to get the results. This makes it particularly good for temporary
content that will be accessed a few times, such as static directions.
•
Fast applications are run locally, are directly compiled, and run
directly on the device’s native instruction set.
•
Medium-speed applications are run locally, but may be interpreted
or may run in a virtual player or environment. Application loading is
likely to be slow, and interaction will not be as responsive as might
be desirable in many action game applications. Online resources
about the platform will extensively discuss methods for speeding up
applications.
•
Slow-speed applications generally have significant network delays
as the application waits for information. While any application
with network access may experience network delays unless the need
for the information is accurately forecasted, browser applications
without AJAX technologies will experience these delays with every
interaction.
4.3 DATA STORAGE LOCATIONS
Many applications store user data beyond temporary interactions,
whereas others do not. The user’s need for persistent storage, either
locally or on a server, varies based on the nature of the data and the
application’s requirements. A calendar needs to be available even when
the network is gone.
The location of data storage is more important for users in areas
with inconsistent coverage, such as US users,
2
Data coverage outside of metropolitan and other highly traveled areas is quite spotty, with
miles of Interstate highways in the West with voice coverage only. While the majority of
the population lives in an area with good coverage, much of the land mass and many travel
destinations do not have good coverage. Additionally even in metropolitan areas there are
coverage holes.
2
but it is relevant for
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many other users. If the application needs to be available while out of
coverage, such as on an airplane or in a tunnel, it should be stored
locally. For these reasons, there will continue to be a need for both
browser-based and locally based applications.
Messaging applications are transient in nature, although the user
can choose to store the results locally. These are good for situations in
which the user’s past input, behavior, or results need not be considered.
However, a messaging connection to a server-based application, such
as messaging access to a PayPal account, can be used to overcome the
transient nature and instead have remote data storage.
Local data storage can have its own issues. Since PCDs can be readily
lost or swapped, any local data needs to have a backup stored on the
user’s desktop computer or a server. This process needs to be carefully
managed.
Remote data storage has high reliability and addresses the issues
associated with loss of device. It has challenges associated with network
access, as discussed above.
4.4 DISPLAY MODALITY
Devices can display information using aural and visual displays. Some
platforms and devices also allow access to the vibration function.
Aural displays can be played via the ear piece or the speaker. In
many situations, sound played via the speaker during an application
will be disabled due to privacy or politeness issues. Sound played via
the earpiece of course makes the user’s ability to see and hear the
display simultaneously more challenging.
Applications thus tend to segregate themselves into those with
sounds playing key roles, and those with sounds playing supplemental
roles. Expect use of the former to be somewhat limited by user situation.
Visual displays are common, and expected for all but speech applications. Tactile displays, such as the vibrator, are accessible by some
platforms. This is notorious for using battery life quickly, but is important for getting the user’s attention in noisy environments.
4.5 SUPPLEMENTAL TECHNOLOGIES
Some platforms provide access to a device’s capabilities beyond button
presses, display, and perhaps the speaker. Of course, device support for
SUPPLEMENTAL TECHNOLOGIES 61
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such technologies is highly variable, but these technologies can greatly
enhance the user experience.
Location, as measured by global positioning system (GPS) or other
technologies, is fraught with privacy issues, enough that many users
will not have it turned on. Java ME, BREW, and native platforms
have varying degrees of access to the information, depending on what
portions of the platform’s capabilities the device has enabled. Java
3
in particular has varying implementation of JSR
179, the location
interface module.
Carriers (or devices) may allow access to location, but only for registered applications. They may allow access, but not at a precise level.
They may even charge for access to the user’s location. Creation of
location-based services (LBS) requires an in-depth analysis of market,
carrier, and device capabilities; you will likely find that only one platform is even an option.
Wireless connections to other devices are also sporadically
supported. Java and BREW applications can access Bluetooth local
networking if the device supports it. Some native platforms also allow
access. Palm and PocketPC allow prolific access to the infrared port
but cross-device platforms have no access.
User data on the device, such as the calendar and contacts, is accessible by native platforms, BREW, and the Java ME PDA profile specified in JSR 75. This data can reduce the need for text entry, provide
a local display for online data, and in several other ways enhance the
user experience for certain applications. For a messaging application,
such access is very important.
Some platforms allow the storage of small bits of data by applications; cookies are the prime example, bookmarks could be considered a
specialized version. Flash and Flash Lite both allow such storage. More
capable platforms have this capability with the standard file system.
Devices will have an increasing number of methods of display. Vibration is often available on current devices; many ‘clamshell’ phones
have a secondary display that can be used by some platforms. Future
devices may have projected displays or even odor-generating displays.
As always, native applications have the greatest access to such features.
BREW has vibrator and secondary screen access; Java ME, in MIDP 1
and 2, has only vibrator access and then only for some devices.
3
Java Specification Request, the specification for different aspects of Java. The Mobile
Information Device Profile, for example, is JSR 37. MIDP 2.0 is JSR 118. Theoretically,
the JSRs that a device supports lets the developer know what is and is not possible on that
device; in practice different devices implement a given JSR differently.
62 SELECTING APPLICATION TECHNOLOGIES
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Devices will also have an increasing number of data sources locally
available. A thermometer or glucose meter might provide information about health issues. Device manufacturers are experimenting with
accelerometers to allow users to gesture to control the devices. Watch
platform capabilities to see what access is available; expect it in native
platforms first.
4.6 DISTRIBUTION METHODS
Distribution methods include both broadcast and point-to-point
models. The former will distribute content at low costs, the latter
allows for on-demand media but suffers from scalability problems.
The future is likely to see a mix of the two, based on media type and
user behavior. See Chapter 8 for more information about distributing
applications.
4.6.1 Cost of Deployment
A platform’s cost to deploy applications is a function of programming
complexity, rendering differences among targeted devices, the carrier,
and cost of getting the application into sales channels.
Programming complexity is inversely related to the platform’s access
to device capabilities. In general, the same things that make a platform
powerful will make it more complex to code. Further, greater access
to device capabilities by a specific application seriously increases the
impact of varying device capabilities and rendering algorithms.
The same technology displayed on different devices will frequently
render very differently. This problem will continue to exist due
to varying user needs across market segments. The problem is
compounded further when an application needs to render in different
(but equivalent) technologies, such as Palm and Windows Mobile.
For some platforms, rendering engines are available. These engines
optimize generic mobile content for display on devices with different
capabilities. A voice SMS engine, for example, would send voice SMS
to devices that support it, and a SMS with a callback number for
devices that do not support voice SMS.
Rendering engines are limited in capability, and are best used for
platforms with limited interactivity on the device or limited rendering
differences. All such engines successfully capture display size; most also
DISTRIBUTION METHODS 63
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capture device capabilities. Few capture device user interface differences or differences in how certain commands are interpreted. Avoid
engines that purport to render to mobile or desktop environments with
the same base code; see ‘Class-based Design’ in Chapter 5 for more
details. Definitely use caution when selecting a rendering engine that
purports to create applications on different platforms based on the
same code: always expect human intervention in translating applications between platforms.
Good rendering engines are available for web sites, SMS, and MMS.
Flash Lite allows rapid recompiling of designs for different device
capabilities, although it is limited in what capabilities it can access. Java
ME rendering differences can be partially addressed using WURFL and
other technologies; again see ‘Class-based Design’ in Chapter 5 for
details.
4.6.2 Sales Channels
Different platforms have different advantages and challenges with
regard to sales channels. These differences are largely due to the
carriers’ business models and users’ willingness to pay for services.
In the United States, for example, SMS has seen slow adoption,
particularly among adults.
instant messaging and suffered from carriers creating barriers to interoperability. Thus reliance on SMS for delivery, except for various
youth markets, will limit penetration compared to voice. However,
SMS is perhaps the most commonly used platform as it has the greatest
coverage and its use is growing.
Web browsers are very commonly available on devices, but the user
has to be able to both find the browser on the phone (difficult on
devices including a Motorola RAZR from Verizon) and have a data
plan that supports browser use in a reasonable fashion. Cingular’s data
plans as of March 2006 had 1 megabyte transfer per month charged
4
The country relies far more on email and
4
US adoption has lagged behind European adoption for a variety of reasons. First, European
operators originally did not expect SMS to be popular, so they priced it for rapid adoption.
Second, high telecommunications costs in Europe meant that computer and Internet penetration, particularly at home, lagged the US. These two facts made SMS a spectacular deal. US
carriers, seeing European SMS success, priced SMS at more of a premium, while email and
instant messaging penetration was quite high among teens and the population in general.
Couple this with different pricing models in the US, such as the recipient must pay to receive
a message, and cross-carrier incompatibility, and the recipe for slow US adoption becomes
obvious.
64 SELECTING APPLICATION TECHNOLOGIES
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at a US$5 monthly fee; larger amounts of data cost $15; unlimited
browser use was $20. Delivering a service using browsing technologies
would be limited only to users who were willing to pay an additional
$20 per month, all going to the carrier. Any content charges would
raise the user bill even further.
The ‘walled garden’ refers to a carrier’s prohibition of content
beyond what the carrier has authorized and contracted for. This practice was predominant in 1999, and still exists with many carriers in
2006. The original intent, at least at Sprint, was to protect business
relationships and maintain a minimally usable user experience. As the
mobile web has grown and more content has become available, the
original intent is no longer valid.
Verizon and Cingular both maintain their walled gardens in 2006.
Thus Verizon does not allow URLs in text messages to be clickable: the
user would have to manually type the URL into the browser. Cingular
has a clause in its user agreements stating that the user will not visit
sites outside Cingular’s properties. The access that Sprint Nextel gives
to their customers to sites outside the ‘garden’ varies, but the user can
always type an arbitrary URL; if it is compatible with the mobile it
will work. Regardless, many users cannot figure out how to enter a
URL, so the on-deck content is most accessed.
Thus a web service would be available to Sprint and most European customers without special relationships, but not to Verizon and
Cingular until they either open their networks or your organization
has a business relationship with them, putting you on their portal.
Check carrier policies in your market for a good understanding of the
challenges you will face.
Even assuming that the networks are open, positioning on a carrier’s
portal may be extremely useful for promoting your service. Certainly the
history of desktop portals suggests this to be the case, with deals associated with the placement of content. Entering a URL on a phone is more
challenging than entering a URL with a full-sized keyboard, so we should
expect this trend to continue. Note that only web services can be placed
on the portal, as carriers are unlikely to place a link to a downloadable
application as a main link on a space-constrained portal.
Downloaded applications are acquired, by users, from three main
locations: the carrier’s store, a third-party store such as Handango, or
the software provider’s own site. For the most part, third-party stores
appear to carry more native applications than cross-device applications
written in Java or BREW. Indeed, BREW’s business model requires
carrier involvement for the sales process.
OTHER CONCERNS 65
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A SMS product does not necessarily involve the carrier, and can
be monetized directly using premium SMS and short codes. It is not
without its limitations. PayPal’s re-entrance into the mobile payment
arena is likely to inhibit the use of premium SMS in the United States
due to a greater familiarity with the PayPal brand and a relatively high
level of trust of PayPal.
The best place for an application is not on the carrier’s portal, but
rather on the device standby screen. Device user interface customization technologies such as Qualcomm’s uiOne allow such access. Some
carriers allow full device access; others have sharply defined what
developers can and cannot do. Some carriers have also recognized
the need to make applications more accessible and the user experience more manageable, and have created favorites, available from the
standby screen, allowing access to any application, web site bookmark,
or component of the device’s user interface.
If your primary marketing channel occurs via the physical rather than
virtual environment, you will not have the opportunity to display all
the carrier and device rules on a poster or magazine ad; your application platform should be selected accordingly. The greatest independence of carriers is achieved with SMS or native applications; the largest
number of devices supported is achieved with SMS, browser, or Java ME
applications.
4.7 OTHER CONCERNS
Unfortunately, the user experience of the application itself is not the only
concern in selecting a technology. Cost of deployment and access to sales
channels are key marketing measures, and an organization’s familiarity
with a specific platform’s base technology is also important. There are
times when an organization needs to step out of its familiarity, but cost
of deployment and access to sales channels are always relevant.
The Carry Principle dictates that devices are small and wireless, so they
therefore have a limited battery life. There are three major demands on
the battery beyond simple standby: screen display, network usage, and
vibration.
Different application technologies draw down the battery differently. Text messaging, for limited interactions, uses very little battery.
In contrast, multimedia messaging uses more both due to the larger
downloads and because the user will spend more time looking at the
pictures than simply reading a message.
Local applications require some processing and a lot of screen
display, so they are roughly equivalent to multimedia messaging.
66 SELECTING APPLICATION TECHNOLOGIES
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Web applications require both screen and connectivity, so they have
higher power requirements than everything except applications using
vibration.
4.8 PLATFORMS
Different platforms have different strengths and capabilities for development. Table 4.1 summarizes capabilities of some standard platforms.
Keep in mind that of all the sections of the book, this is the one most sensitive to changes in technologies. Before making final technology decisions,
researchthe most recent capabilities of a platform and monitor how much
of the device market has the updated technology.
Messaging is a catalyst technology, enabling a more robust user
experience for myriad applications. A voice-only application can send
requested information via messaging, adding visual and local storage
components to the experience. A message to a short code can return
a link to an application or web site, bypassing complex URL entry
while providing user identification to the server. Indeed, messaging can
enhance the experience of an application built on almost any platform,
if the application is built to handle it.
Applications can certainly be written with messaging alone, and the
selection of text, voice, and multimedia messages gives an array of
possibilities. These are asynchronous in nature, with local data stores.
Note that text messaging is essentially a command-line user interface. All reports of ‘ease of use’ are largely a function of access to text
messaging on the phone and environmentally available help prompts.
Any application with extended text messaging input needs to be carefully designed with robust input processing on the server.
Mobile browser technologies started with HDML and proceeded
to the Japanese cHTML and the European and American WML.
These technologies merged, in a way, to become WML 2.0, which
is XHTML Mobile Profile plus extensions allowing the advanced
navigation features found in HDML and early WML. Unfortunately,
few browser vendors implement the navigation features, and some
implement only XHTML Basic, so the de-facto standard for new
development is XHTML Basic
stripped-down CSS.
5
– with external style sheets using a
5
XHTML Mobile Profile is XHTML Basic plus the tags <b>, <big>, <fieldset>,
<optgroup>, <hr>, <i>, <small>, and <style>, the ‘style’ attribute, the ‘start’ attribute
on <ol>, and the ‘value’ attribute on <li>
Multi-device
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deployment
cost
b
a
Medium
Medium
(MMS); low
c
(SMS)
Storage Display Supplemental
Table 4.1 Platform characteristics
Interaction
responsiveness
Visual Low Low
cookies
(varies)
Local plus Visual, aural Medium
with device)
Medium (varies
(varies)
None Medium
only)
Visual Medium
cookies
Local plus Visual, aural High Medium
level)
Fast Local Visual, aural Very high High
speech
sometimes
Platform Input
Buttons Slow Remote plus
VoiceXML Speech only Fast Remote Aural None Low
Standard browser
(XHTML, cHTML,
WML, CSS)
Java ME Buttons (visual,
possible)
BREW Buttons, visual Fast (native
Buttons Medium Remote plus
Scripted browser (web
2.0, AJAX)
SMS, MMS Buttons, visual Asynchronous Transient Visual (SMS is text
Buttons, visual,
Flash/Flash Lite/SVG Buttons Medium Local plus Visual Low Medium
uiOne Buttons Medium Local Visual High Medium
Native (Palm, MS
speech
eMbedded C++,
Symbian C++,
Buttons Medium Local plus Visual, aural Medium High
Linux)
Abstract Native
(Python, OPL)
3GPP, 3GPP2, media Buttons Slow Remote, local Aural, visual None Medium
There remain enough rendering differences in devices that testing on multiple devices is desirable.
Scripting capabilities are highly variable across devices.
Flash requires separate compiles for different device configurations, although the same design often can be used.
a
b
c
68 SELECTING APPLICATION TECHNOLOGIES
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Some browsers also support scripting, although this requires more
processing abilities. Opera Mobile supports full AJAX, but only for a
limited number of devices. Expect AJAX access to local data stores to
vary almost as much as Java ME’s access to local data stores. Other
browsers support ECMAScript only; again, support is highly variable.
Java ME, BREW, SVG, and Flash Lite were all designed as application platforms with cross-device porting. Similarly, OPL was designed
for rapid development of applications to run on myriad Symbian
devices. As such these platforms abstract the capabilities of individual
devices to a (mostly) common set of capabilities, and do not have access
to other device capabilities. Flash Lite, for example, cannot access the
volume buttons on a phone; many Java ME MIDP 1 and 2 phones
have no access to volume control.
Cross-device application platforms have several implementation
issues, particularly when different vendors write the application environment. Applications are supposed to work across devices, but this
fact needs to be tested. It is not uncommon for the quality assurance
team to be twice the size of the development team for a Java ME
development organization.
Native application environments, such as Symbian C++, PalmOS,
Linux, and MS eMbedded Visual C++, allow deeper access to the
device capabilities than do the cross-device platforms. They run in the
native operating system, rather than in an interpreted environment or
virtual machine. They are faster, with greater access, but with very
limited cross-device portability.
uiOne and similar technologies allow the transformation of the
device’s user interface, particularly the standby screen. Most such
technologies merely change the graphics, font, colors, and layouts of
existing functions on the phone; uiOne has been combined with BREW
to give it native-level access to device development. These technologies will have limited control over the phone, either from the inherent
technology or from carrier limitations.
There are a number of media play technologies, including those
based on MPEG 4 and MPEG 2, Windows media, and so forth. Device
support varies wildly, but translating content is relatively painless so
all formats can be distributed.
5
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Mobile Design Principles
There are fundamental concepts of design that apply across all design
domains, but each domain interprets how these design principles apply.
For example, one fundamental design concept is Fitt’s Law, which
states that the time to acquire a target is a function of the distance to
the target and the size of the target. The further the target is away from
the user’s current position, the longer it takes to move to the target.
The smaller the target, the more the user has to use fine muscle control
and hence take more time to move.
While Fitt originally worked on control panels and studied muscle
and limb movement, the basic concept has been extended to cursor
movement on computer screens.
The implications of Fitt’s law varies design by design, domain by
domain. The size of a target is affected by input mechanism, such
as direct manipulation, cursor manipulation, or scroll and select. The
distance to a target is affected by display and input mechanism, such
as physical controls, computer screen with mouse, serial input (scroll
and select or pure keyboard input), or small screen with stylus. What
follows are some examples in different domains:
•
Hardware control panels. Group controls used together or in
sequence make important controls large and centrally located.
•
Mouse-driven interfaces (software). The ‘large’ controls are the edges
of the screen, as they are really infinitely large in one direction.
Corners are larger still. Thus frequently used items should go around
the edges. The existence of a cursor gives a precise definition of
‘close’, so contextual menus can be truly context driven.
Designing the Mobile User Experience Barbara Ballard
© 2007 John Wiley & Sons, Ltd
70 MOBILE DESIGN PRINCIPLES
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•
Mouse-driven web sites. When a link is activated, the screen changes,
possibly completely, and the edges of the screen are not accessible
by the web page. Thus ‘where the cursor is’ is the largest target, and
cultural visual scanning practices are used to place most elements.
Consistency between pages helps the visual scanning process. Note:
modern web development techniques allow for an interaction style
more closely resembling software.
•
Stylus-driven interfaces (small screens). The concept of ‘distance’ is
almost meaningless, as the entire screen is smaller than the hand and
there is no cursor. Thus size and predictability of location become
the key issues for speed of target acquisition.
•
Scroll-and-select interfaces (small screens). The number of keypresses to access a target is a good measure of distance, and size is
reasonably represented by whether the target is currently displayed
or not. As more devices display several font sizes, target size will be
a combination of visibility and target size.
Note that in all but hardware control panels, the keyboard is a
known distance away (short distance) but suffers the challenge of no
visual display-control association (small size).
Some issues are present in the full-sized computer world, but are
exacerbated in the feature phone world. For example, phone users,
like personal computer users, are not power users. This can result
in features for users perceive as invisible, notifications not being
dismissed, applications installed in main memory without concern for
memory available, and even expired applications still on the device’s
main screen. Further, users do not necessarily understand memory
management, and may believe that simply by inserting a memory card
they have more memory – even if they never move anything to the
memory card.
In addition to novel interpretations of known design principles, the
mobile space has several unique principles. Each will be discussed and
implications discussed.
5.1 MOBILIZE, DON’T MINIATURIZE
First and foremost, simply transferring a full-sized computer application to the mobile environment almost always results in a suboptimal
mobile experience. Attempting to construct an application that works
the same on both platforms will reduce its quality in both places.
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A full-sized computer does not have integrated cameras or reliable
voice communications; a personal communications device will not have
a readily usable full-sized keyboard or large screen. Desktop users are
primarily interacting with the computer; mobile users may primarily
be interacting with the world, both through a mobile device and in
person.
Mobilizing an application means reconsidering the entire purpose of
the application, not just changing display technologies or interaction
nuances. How do your users’ needs change when they are no longer
at their desks? Does your application even have a place in the mobile
environment? Or, is your application one that doesn’t make sense in
the full-sized computer environment?
What mobile technologies best meet your mobile users’ needs? SMS?
Camera? Web? Symbian? Windows Mobile? Java ME? What devices
are your users using, what carriers are they using? What features and
services might they want in the future? Are bar codes a relevant part
of the use environment? What about bar code readers – or perhaps
the camera will be sufficient? How does the user’s location affect the
application’s understanding of the user’s context? Or is the location
merely a method of reducing text entry?
Indeed, this concept, to rethink what is desirable and possible for
the mobile environment and to build and rebuild accordingly, is the
main premise of this book.
5.1.1 The Carry Principle
Personal communication devices differ from computers in that many
if not most users always carry the device with them. This has several
important implications for the mobile device and service design:
•
small device – users won’t carry large devices
•
multi-purpose – users won’t carry a variety of single-purpose devices
full time
•
personal device – the device is not shared, and is likely to be
customized
•
always on, always connected – instead of being turned on only for
use, PCDs are turned off only to preclude interruption for various
temporary reasons
•
battery-powered
•
wireless – and thus inconsistent –connectivity.
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5.1.2 Small Device
The most obvious implication of The Carry Principle is that the device
must be small enough so that it can be readily carried. The device will
not always be with the user if it is bulky or heavy. This, in turn, triggers
certain design constraints.
A small device, with a small screen, can effectively display only a
single window at a time, with dialog boxes and menus. The user can
thus use exactly one application at a time. An interrupted application is
truly interrupted unless the device returns focus to the abandoned application. The handling of interruptions varies drastically across different
devices and platforms.
Most devices are good at managing incoming messages during application use but ineffective for launching other applications or calls while
maintaining application status. In particular, some browsers return the
user to the home page upon each launch; these browsers cause the user
to lose track of what was happening before the interruption.
The interruption problem also exists for Java and other platforms.
The time to launch the application can reach thirty seconds, so an
exited application reduces the likelihood of continued application use.
The single-window interaction also causes challenges in accessing
information outside the application. Just as the phone book needs to
be available during a voice call, movie information might be useful for
a chat session. Applications should provide access to any information
resources that might be needed to successfully use the application.
One-Handed Operation
Although PCDs can certainly be used with two hands, they will
frequently be used with one hand. Expert users can type one-handed
without looking at the screen.
A stylus-driven device may also be thumb-operated. If your touchscreen application will be used on the fly, you should also support
thumb operation with larger controls for certain actions. Many users
will only use the stylus when interacting with the application for
extended periods, or to enter text.
Users may be interested in using your application surreptitiously,
such as under a table at a meeting without looking. To support this
behavior, ensure that common tasks have a stable set of keystrokes to
complete the task. In particular, do not insert any controls between
MOBILIZE, DON’T MINIATURIZE 73
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where the cursor is (or starts) on the screen and the main task controls
for the screen. Note that this also makes your application more accessible to the blind and vision impaired.
Difficult Text Entry
Even on devices with easy text entry, such as a thumb-sized QWERTY
keyboard or an integrated alphabetic keypad like Fastap, text entry
is more difficult than on full-sized computers. Frequent users of text
messaging may type relatively quickly, but they do not do it for any
length of time (text entries tend to be short) and they use shortcut
abbreviations wherever possible. Intrinsically, they recognize that text
entry is difficult.
Predictive text is also relatively difficult, even though it makes a hard
task easier. While expert use of QWERTY keyboards and even triple
tap involves focus on the screen, most letter prediction mechanisms
create significant cognitive dissonance if focusing on the letters. The
user can be typing one word, but the screen is displaying another
because that letter combination is more frequent. This can slow down
the text entry process.
In the future, full-sized QWERTY keyboards may be more common.
Currently available are rollable fabric keyboards and infrared keyboards
1
projected onto flat surfaces
requiring no separate accessory. These solutions work well in certain use situations, such as taking notes at a meeting,
but they will not be the standard input mechanism for PCDs.
Use of any full-sized keyboard requires a surface upon which to place
the device, a surface upon which to place or project the keyboard,
and the ability to type with both hands. The user’s mobility is thereby
limited to that of a laptop computer. If your application requires this
degree of immobility, consider a laptop or tablet computer as your
application platform.
2
1
Note that projected keyboards provide no tactile feedback when a key is pressed and thus
forces the user to watch the keyboard and not the screen. Still these have promise for certain
niche users, where a keyboard projection could be ‘thrown up’ for use in contexts where either
work demand (text quality or quantity) precludes other alternatives. A number of niche uses
(medicine, higher education and the military) exist for such keyboards.
2
Some inventors have created truly virtual keyboards, requiring no surface upon which to
project. These ‘keyboards’ instead track finger positions. This will remain at best a niche
solution to the text entry problem due to the requirements of touch typing and wearing
sensors on the hands. Further, they still require a surface upon which to place the device, so
there is not a significant advantage compared to the fabric or projected keyboards.
74 MOBILE DESIGN PRINCIPLES
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As for mobile devices, reduce text entry as much as possible. Pick
lists (drop-down menus or full-screen lists) convert some tasks to cursor
movement. Other input sources can include:
•
Global Positioning System (GPS) or other location services eliminate
the need to enter current location for services ranging from finding
a local movie to directions to a day runner.
•
Cameras can take pictures of bar codes or other code systems.
•
Cameras can take pictures of text, including product packaging,
business cards, and receipts.
•
Address books or calendars can reduce input in certain classes of
applications.
•
Auto-completion3(built into some devices’ general text entry mechanisms) reduces keystrokes for long words; this mechanism also can
be added to individual applications.
•
Image recognition of faces or objects can be very useful. Consider
a camera application, on a PCD or on a standalone camera, that
organizes pictures using similarity of faces or locations. All of the
pictures of Betty are tagged ‘person 1’, which the user can rename
as ‘Betty’. All pictures taken at a specific restaurant, if recognizable,
would be tagged as such and those in a specific time range would
be tagged as a specific meal. Image recognition could also be used
in a tourist direction-finding application.
•
Date and time can be extracted from the PCD. The server time can
also be used, but may not be in the user’s current time zone. The
application context will dictate which is preferred.
•
Speech, processed at the server using dictation technologies or
VoiceXML, can be used in a multimodal application. Many applications would benefit from adding a speech element, something that
is more possible with packet data networks.
Small Screen
A small device dictates, to some extent, a small screen. Many PCDs
will retain familiar LCD screens, but future devices may have a flexible
rolled display that enables a larger screen.
Small screens cannot support multiple windows; the space dictates
only smaller sizes of layered information be used such as drop-down
3
Both Tegic/AOL’s T9 text entry and Zi Corporation’s eZiText suggest words from the
dictionary that fit the current input.
MOBILIZE, DON’T MINIATURIZE 75
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menus, pop-up menus, and small dialog boxes. Thus the user will
visually interact with only one application at a time, using only one
window. An ‘open in new window’ link is the same as a normal link
on a web page.
With mobile devices, users will have an even lower tolerance for
screen rendering delays than they do on full-sized devices. Pre-fetch
data whenever possible to speed information rendering, but be sure to
provide a mechanism to turn this off for users who have to pay for
each byte of data. Consider using a local application rather than a web
application for rendering intensive services.
Small screens also prevent the user from smoothly reading large
chunks of text. There are three reasons for this. First, it is easy
to lose context when scrolling, as the physical and cognitive efforts
of moving from page to page interfere with reading comprehension. Between-screen continuity is broken. Second, glare and pixel
issues make the actual font difficult to read. Third, well-practiced
text scanning behavior is not supported. Most people scan text for
nouns or phrases to comprehend text, but the frequent line and page
4
breaks coupled with the lack of negative space
makes this difficult
to do, forcing users to read word by word rather than phrase by
phrase.
Mobile content must be carefully designed for the small screen and
lack of user focus. It could be argued that this one of most significant
design challenges mobile designers face. It may be that we will have to
rethink the page metaphor in much the same way we have to reject the
personal computer as a model upon which to design mobile devices.
This problem of mobile content creation will be more complex when
public-use displays become prevalent. This could create the possibility
of approaching a display at home or at work and seeing the information
and applications from the handheld device displayed on large displays.
In this case it will become necessary to switch from a single-panel
display to a multiple-window display. As of 2006 no such system exists.
5.1.3 Specialized Multi-Purpose
Users want several features; marketers, vendors and the mobile industry
will want users to have even more. Some, or most, of these features
4
In visual design, negative space, or white space, is the area the eye does not register. It is
used to show the eye what path to follow. Small screens filled with text have little or no
negative space.
76 MOBILE DESIGN PRINCIPLES
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are available on focused-function devices: digital cameras, iPods,
televisions, GameBoys, calculators, and watches are all viable useful
products. Few people are willing to keep all these devices in their
pockets at all times. But the question remains how to determine which
of the many functions should be implemented device by device, market
by market. Answering this question requires further empirical research
into mobile user needs – a task many device manufacturers have
refrained from either underwriting or doing themselves.
Focused-function devices, or information appliances, are devices
built around a single purpose. Other functions may be available – the
iPod has a calendar – but the main experience is not sacrificed in any
way. The calendar does not impinge on the music experience. Information appliances are used by people who cherish the experience of
using the particular feature or service.
The Carry Principle dictates that PCDs be multi-purpose devices
somewhat like computers. The PCD will first have all the features
that are desirable but are not, in the user’s opinion, worth carrying
a separate device to experience. Further, even features that do merit
an information appliance (single devices) will be included in the PCD
simply because it is always with the user whereas an information appliance typically is not. If the experience of using a feature is important
enough to the user to justify an information appliance, this user would
likely appreciate having access to the experience at any time. There
is also of course a market logic for providing mobile users with the
features they typically associate with information devices.
This is not to say that there will in the foreseeable future be a stabilization of PCD design like there has been with personal computers.
Different features are important to different people, and for mobile
devices these features radically affect device design. A person who plays
games to fill time while commuting may be content with five steps
to start a game and generic phone controls; a dedicated gamer might
prefer a GameBoy phone. Both devices could have the same features,
but very different design.
Already popular are ‘hiptop’ and BlackBerry devices, which focus
on text messaging. Some of these are fully functional voice phones for
people who prefer text to voice communications. Form factor proliferation will continue as long as new niches are identified. In fact there
is a market opportunity for vendors and service providers who can
provide as much differentiation as possible regarding both devices and
services.
MOBILIZE, DON’T MINIATURIZE 77
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Bluetooth and other local near-field wireless technologies have the
capacity to connect devices together, which is important for users who
use multiple information appliances. A separate PDA ought to be able
to cause a phone to call or text a specific contact. A GPS device ought
to be able to use addresses from the PCD. A device should be able
to access the Internet via a local wireless connection. This capability
allows an even wider array of devices to share PCD characteristics.
Thus The Carry Principle dictates that feature creep abounds, but
that there will be no stabilization of design. Users would not want the
same shaped device any more any more than they would all want the
same type of automobile.
User Interface Styles
Devices have their own particular user interface styles, with customary
use of softkeys or typical organizations and visual styles. There is
no common style, due to manufacturer differentiation, manufacturer
patents, and different needs with different capabilities.
A simple, low-feature scroll-and-select phone is best used with some
type of rocker key and activation. Nokia-style softkeys (‘Options’ and
‘Back’ as the softkey labels) are common but do not test well with
novice users; softkeys aren’t even required for good design. Some
phones have both an activation button (‘OK’) and softkeys. Regardless,
the user is accustomed to her device’s user interface.
Matching the device’s user interface style is important to usable
applications. Some markets have gravitated towards standard interface
paradigms across manufacturers. In India, for example, devices tend to
have a Nokia-like Options/Back softkey user interface because that is
expected. The Nokia interface is thus, in India, regarded as intuitive.
Scroll and select phones with a large number of features can suffer
from the default tree hierarchy paradigm breaking down. The large
number of features force users to navigate deep into a complex hierarchy unless the desired feature is one of the small set that are readily
accessible – and recognized as such. The industry is seeing the emergence of new methods for working with large amounts of features and
content using the same interface methods. Content and features can be
accessed through bookmark-like favorites. Themes allow user interface
customization, pushing preferred features higher up in the hierarchy.
Expect new paradigms, such as organization by frequency of use and
meta data, to emerge.
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Stylus driven devices have more flexibility in user interface, and use
that flexibility for market share differentiation. But some users reject
stylus use and find the hand–eye shifts between stylus and touch difficult to master. Windows Mobile was designed to support large quantities of features and content; Palm was designed with fewer capabilities
in mind.
Each user interface has its own advantages and disadvantages, but
provides the context for your application. Among other things, this
means that testing your application on an arbitrary device will provide
little useful data for users accustomed to a different device.
Some platforms, particularly Java ME, try to account for user interface differences by not specifying how certain features are rendered.
In theory this allows the application environment to match the device
user interface. In practice, device manufacturers seldom consider the
impact of the application environment implementation on the user and
simply do not specify how the environment should be displayed.
5
Rendering Idiosyncrasies
Devices have different capabilities, input mechanisms, display characteristics, and user interface paradigms. Due to varying user needs, this
will remain true. Thus rendering differences, and the resulting opportunity for creating competitive advantage, are a fact of life.
Further, even standardized platforms have their implementation
problems. One browser developer may have decided that background
images were inappropriate in the mobile space. Another may have been
unable to code proper table behavior due to limited processor capabilities. One designer may have thought that both softkeys could bring
up menus; another designer may have limited menus to the second
softkey. These differences can exist even with devices with largely the
same characteristics and largely the same user interface. This of course
raises questions for users and can make devices with the same features
and standard platforms seem counterintuitive.
Rendering idiosyncrasies, combined with differences in feature
implementation, cause ‘write once, run anywhere’ to be an unfulfilled
dream. We do not expect the dream to be fulfilled. See ‘Handling
5
This statement is made based on both observation of myriad devices’ implementation of
Java ME’s KiloByte Virtual Machine (KVM) as well as experience working with carriers and
device manufacturers who did not have KVM implementation anywhere on their priority
lists.
MOBILIZE, DON’T MINIATURIZE 79
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Device Proliferation’ later in this chapter for some suggestions about
how to manage this challenge.
5.1.4 Personal Device
A PCD is like a wallet or a purse: its loss will be noticed and rectified quickly. Its connectivity will be discontinued, and transferred to
another device. The carrier may be able to remotely erase the device
so the data is unavailable to anyone who acquires a lost device. These
simple facts have a number of implications for the design of security
in applications:
•
Password entry need not be masked. The user can readily hide the
screen from onlookers, more easily than hiding which keys are being
pressed. Further, the difficulty of text entry makes password entry
costly to the user experience. Of course, some applications do indeed
need that extra security, but those are rare.
•
Account cookies should not expire quickly. The fact that users will
disable their network access upon device loss means that any thief
cannot get to sensitive online data.
•
Some sensitive data can optionally be saved on the device. If the user
is known to have access to remote erasure of device, then private
information can be stored there.
5.1.5 Customized Device
Ringers, wallpapers, stickers, and face plates are some of the ways users
customize their PCDs. Because they are personal and visible, PCDs can
become statements about the personalities and status of their bearers.
The device is an accessory as much as it is a communications tool. In
effect personalization (and the market advantage it offers vendors) is
something that makes mobile device design a different kind of technology and marketing arena than personal computers.
Newer devices can also allow customized user interfaces, sometimes
known as themes, which allow for further personalization. The increase
in popularity of this technology means that even if an application
knows what model device is being used, the exact environment, even
user interface, is not guaranteed.
The importance that customization has for mobile users needs to be
explored more. But essentially we believe the market for customization
80 MOBILE DESIGN PRINCIPLES
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could in time rival the market of goods and services like data and
data delivery in the mobile industry. Certainly the current commercial
success of ring tones suggests this will be the the case.
5.1.6 Always On, Always Connected
Society is still learning how to deal with prevalent mobile phones, with
alerts to turn phones off in theaters and nasty glares when a phone
user is being discourteous. There are fewer and fewer places where one
can escape from mobile phone intrusion.
While public rest-room culture may not appreciate mobile phone
conversations in rest-room stalls, voice phone use does exist. In all
likelihood, there is significant non-voice use of PCDs happening in restroom stalls. Theaters and churches exhort people to turn their phones
off; many instead switch phones to silent or vibrate modes and they
resort to text messaging.
These examples illustrate the degree to which not only is the PCD
always with the person, but that it is always on. Many users often feel a
kind of withdrawal when disconnected from the virtual world, whether
accessed via their mobile devices or their full-sized computer. This
feeling of loss is similar to what many people feel when disconnected
with their television.
5.1.7 Battery-Powered
A carried device is not connected to a power source but is instead
powered by batteries. In places with unreliable electricity, this actually
makes carried devices more reliable than many fixed-location devices.
Battery power and wireless connectivity could go a long way to equalizing the infrastructure inequalities between industrialized and lagging
economies.
Although the mobile user is not tethered to an electrical cord during
use, she still cannot roam far without a charger in her briefcase. She will
have to reconnect at the end of the day. Batteries with large capacities
are available, but their larger size makes the device heavier.
Most people will not want to charge their devices every day.
Processor power, screen display, and connectivity all increase the
demand for power. Size limits the supply. This power restriction means
that anything the device can do to limit power use, such as dimming
the display or even using powerless displays, should be considered.
MOBILIZE, DON’T MINIATURIZE 81
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Similarly, anything within reason that an application can do, such as
reducing connection time, not waking the display when unnecessary,
and reducing processor demands, it should do.
5.1.8 Inconsistent Connectivity
A carried device is by definition connected to information sources wirelessly, and from different locations. Wireless networks have service
holes or outages. Cellular networks have dead spots, especially in the
United States but also in tunnels and basements worldwide. Wi-Fi
hot spots are inherently spots (and thus spotty), and further have a
limited number of possible users. Even wide-area wireless networks
like WiMAX will have dead spots, limited coverage, and the inability
to penetrate to the middle of the mountain. Thus inconsistent connectivity is an integral part of using a PCD, especially when on the
move.
Applications need to be designed to handle inconsistent connectivity
gracefully. One reason users rejected early WAP implementations was
due to a failure to handle this problem. Nokia browsers
connection to the Internet to run, and when the Internet connection
dropped the browser exited, even if the user was merely looking at a
page and not requesting data. To make matters worse, these browsers
always started at the home page when launched. Thus a user who
dropped coverage for even a second while trying to accomplish some
task would find all his work erased and unrecoverable.
SMS gateways handle inconsistent connectivity by resending the
messages when delivery fails. This is an excellent method of handling
the problem, but marketers should avoid using the term ‘instant’ when
describing text messaging.
If your application contains infrequently changing data to which the
user needs reliable access, a local application is better than a web application. Pre-fetching data, whether in a web application or a local application, will help ensure that the data is available when the user asks
for it – whether the network is or not. Unfortunately most browsers
today have very limited pre-fetch support.
6
required a live
6
Nokia’s chief browser competitor at the time, Openwave, encouraged calls to drop to
avoid costs, and started at the last visited page to avoid loss of work. Unfortunately Openwave’s feature list was not well known or understood, and Nokia’s failings affected the
entire industry. Usability guru Jakob Nielsen, in his company’s report about WAP usability,
condemned the entire WAP concept based on Nokia behaviors.
82 MOBILE DESIGN PRINCIPLES
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5.2 USER CONTEXT
A desktop computer user is sitting with a computer at a desk. A laptop
user might have taken the computer to a coffee shop, library, airport,
or meeting room but largely will be sitting with two hands on the
keyboard, the device on some surface. Mobile device contexts are more
varied, and more difficult to predict and discover.
Mobile devices share with ubiquitous computing the ability to
discern user context. Where mobile devices make assumptions about
one user entering various situations, ubiquitous computing systems
make assumptions about all people who enter a space. A ubiquitous computing device can be set up to take into account facts about
the immediate environment, what information is available, and what
tasks are likely, and displays information accordingly. The mobile
device knows nothing about the environment but has the resources and
features that could enable it to learn much about its user.
Myriad sources of information are possible, some gleaned from the
environment and others intrinsic in the information on the device:
•
Geographic location, such as from GPS, can determine travel status,
whether the user is likely to be late for a meeting, or what the user
is doing. For example, if the user’s location is on a train line, the
user is probably on or waiting for a train.
•
Precise location, such as from a Wi-Fi network, Bluetooth, or an
7
RFID
information transfer.
•
Motion and temperature sensors within the device can detect user
movement, air temperature, and gestures. These could possibly be
combined to intuit mood.
•
Calendars can provide likely user activity. If the user is in a meeting,
sending advertising is inappropriate. However, sending industry
news may be very appropriate.
•
Cameras can either capture images directly, or recognize image
contents such as bar codes, faces, traffic signs, or other environmental data.
•
Local data sources, accessed by Bluetooth, RFID, Wi-Fi, or other
mechanisms, can be used to allow the local environment to talk to
reader, can enable extremely targeted marketing or very local
7
Radio Frequency Identification tags are inexpensive chips that can have information stored
on them; they can be read by nearby readers but require no power themselves. A phone
could have a chip, a reader, or both.
HANDLING DEVICE PROLIFERATION 83
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the mobile device. A store shelf transmitter could offer a coupon
for 20% off a specific product, as long as it is purchased within the
next 15 minutes.
•
Other personal devices can provide a wide array of information,
limited only by designers’ imagination. Apple’s Airport Express,
which can route music from iTunes to a stereo, provide a stationary
example of device interaction.
•
Other users’ mobile devices are another source.
When these and other information sources are combined intelligently, they can give the users enormous benefits which we are
beginning just to explore and exploit. Travel applications can combine
several of these sources with online information to alert the user when
she needs to leave for the airport, even in an unfamiliar city. If the
user is out of the office and near restaurants at lunch, any place with a
special or matching the user’s food interests could send information to
the user.
As time goes on, more sources of context will become available.
5.3 HANDLING DEVICE PROLIFERATION
Device proliferation is a reality of mobile application design. Many
attempts have been made to create some platform, some technology
that allows developers to write once and have the application run on
every device, but none has succeeded. Sun’s Java ME (itself a platform
targeted at a class of devices) has itself expanded into many nonstandard implementations partially driven by devices with different capabilities. Different browsers have different capabilities, and different
carriers allow different functions.
Handling device proliferation is a necessity. There are four basic
approaches to designing an application to run on multiple devices:
•
Targeted – select a set of targeted devices (mobile and full-sized) and
then write an application that works on them only.
•
Least common denominator – select technologies and designs that
will work on all devices (includes graceful degradation of code such
as <code><noscript></code> tags in web pages).
•
Automatic translation – use a technology that converts some standard core function, perhaps written in XML, into the format needed
by each individual device for ‘optimal’ design.
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