In 2007, Adaptive Path conducted a significant amount of research and design work in the mobile space. Typically, we can't talk about much of it, though the paper Rachel co-authored with folks at Nokia addresses some of it.
In discussions on designing for mobile, form factor often dominates. The devices have to fit in your pocket. They have smaller screens. They have (or don't, in the case of iPhone) some set of buttons.
Another common theme is "they're not small PCs." Initial attempts at mobile design tried to squeeze the PC (particularly the PC Web experience) into the phone, which simply frustrated users.
What I've seen in our work is that form factor, though important, is not crucial. In fact, it might be a misleading concern. The thing that's interesting about designing for mobile isn't the form of the device. It's that the device comes with you.
What we're realizing is that the key item of concern when designing for mobile is the context in which the device is used. What this means is that discussions of "PC" versus "mobile" are misguided, because we shouldn't be focusing on the device. We are not designing for mobile — we're designing for mobility.
It's helpful to contrast designing for mobility with designing for sedentariness. What we hadn't realized until we were designing explicitly for mobility is that, in the past, we had been designing not just for the "PC," but for a sedentary experience. We shared unstated assumptions that people would remain in one place for long periods of time, with little change in their environment. We could take advantage of this with software experiences that rewarded deeper engagement, encouraged exploration and play, allowed for more complicated interactions to achieve a goal.
A key characteristic of mobility is that the environment around the user is dynamic — they're walking, driving, on transit, in restaurants, theaters, offices, moving from place to place, context to context. Things around them are constantly changing.
And what we as users want in that kind of dynamic environment is a highly predictable, straightforward, get-in-and-get-out software experience. We don't want to explore cyberspace when we're out-and-about. We want to quickly get a key piece of information, or make a key connection. We want key functionality at our fingertips.
Whereas in a static environment, we're much more willing to explore, assess, and analyze. We're willing to take the time, to try new things, to invite surprise, because our environment is stable and supportive. So there's an inverse relationship between the dynamism of your environment, and the complexity of use you're willing to put up with.
Now, the thing is, it doesn't matter what device you use in these contexts. If I'm out-and-about, and I pull out my laptop to find an address, I want to get in and get out. And if I'm at home or at the office, and have time to relax and engage, I'm perfectly willing to get exploratory with my mobile phone.
I believe we're missing big opportunities when we design for the device, and not for the context in which the device is being used.