You'd expect long-form writing to be unthinkable on today's mobiles, but plenty of people wrote whole novels on Palm PDAs with only the on-screen keyboard/Graffiti. I also performed extensive text entry on Palm PDAs for my middle/high school notes and assignments, and didn't consider it a bad experience. And these examples, and the above commenter with his Sim City clone for the TI-82, demonstrate, when you make up your mind that you're going to do something on a limited device, it's often surprisingly possible.