There's also a tradition of adding.. ista.. and ist on to words.. mobista.. mobilist.. mobilista.. (just looked online, I see squatters have already got two of those). Also.. mobilizer.. socializer.. but don't do the flickr thing if you don't have to..
Making plays on words other people have suggested.. I'd look at shoutspace, textspace.. shouttext.. textyell.. hollaspace.. mobiile.. txtmobl..textpush.. socialpush.. sociplace.. freesocial.. soctxt.. txtpush.. textero.. socialpath (play on sociopath?) no idea if any of those are taken or used yet.
Do NOT name it anything having to do with Twitter.. or put an i in front of it.. that is totally done already.
One of my ongoing projects is called Workpost. It's a place to post and find work and, soon, will be a place to list and review workers. We have other stuff planned for future versions of the site + application but it all originates from the name and the brand.
It's cool if you can think of a nonsense word and then turn that into a brand but with all the web 2.0 names out there, I think it's more useful now if you can start with a name that already means something.
Well, hope that was helpful.
I've never used it and TBH am unlikely to ever get around to doing anything on it. I'd rather it got used than sat there.
If you'd like it, you can have it at cost. Just buy me a beer one day if you make millions ;-)
It's very Web 2.0. Might need to rename when Web 3.0 beta comes out to make it compatible.
I own this but am not using it.
I have, but am not using, the .com domain.
(just kidding, that's actually a horrible name)
mogtown.com (available)
Take a descriptive word, drop a vowel - how novel. Try coming up with a unique brand without following the same formula as everyone else - Google, YouTube, Facebook and MySpace all managed to without going the Flickr route.