In the last issue of ACM interactions, Lars Erik Holmquist's column is about designing mobile applications. He starts from a not-so-commonsensical take (at least for app developers):
the accepted wisdom from decades of research on interfaces for stationary computers simply does not hold for mobile devices. You will even hear HCI researchers and UI designers complaining that mobile devices are too small and "limited" to permit anything interesting. But the real difference has nothing to do with size. Instead it comes down to the fact that what we do with mobile computers and the situations in which we use them are fundamentally different from what we do with the desktop. (...) Mobile devices follow us through the day, which means that they are used in many shifting roles
Then he presents what he's doing at his lab:
The goal was to investigate mobile services that, rather than just being smaller versions of desktop applications, take advantage of the fact that they are inherently mobile.
Many of the mobile services that were created in the project were based on local interaction. For instance, MobiTip from the Interaction Lab lets you share "tips" with other users in the vicinity through a Bluetooth connection. (...) Another example of local interaction is the Future Application Lab's Push!Music. What would happen if the songs on your iPod had a mind of their own? In Push!Music, all MP3 files are "media agents" that observe the music-listening behavior of the user and other people in the vicinity. (...) The eMoto project by the Involve group extends the possibilities of mobile messaging by adding an emotional component. By shaking, squeezing, and otherwise mistreating the phone's stylus after you have written a message, you generate a colorful background pattern that expresses the emotion you want to put across.
And this actually nicely exemplifies his claim about mobile design:
Those who still worry about the "limited" interaction possibilities of mobile devices should note that all the applications mentioned above could be used on a standard mobile phone today (with small modifications). Yet at the same time they drastically expand the interaction parameters of mobile devices by taking advantage of local interaction, observations of the user's behavior, physical input, and so on.
Why do I blog this? I like this emphasis on taking advantage of external elements in the interactions (spatial proximity, tangible inputs...) and not relying on a limited input/output device.