Total speculation, of course, but fun
Since it is supposed to have EVDO, there are a bunch of things that they could do with it.
1) Deliver newspapers, rss feeds and other content right to your device without playing PC games that are too complicated for most people to mess with.
2) Blackberry Competitor. How would you like to be able to read your email, surf the net, download/play music and books, etc. using a Viziplex E-Ink device and 'real' (although mini) keyboard? You could probably write off the expense of the device too, which helps a little.
3) An IM client. There's nothing to say you couldn't IM friends.
4) a VoIP client.Why not talk to them too.
Things I'd like to see...
Detachable keyboard
to reduce the form factor. I'll probalby mostly be reading, so the keyboard isn't necessary.
Either 'Pay as you go' EVDO charges or subscription fees.
My 2c,
Ralph