I was reading a tweet by @haacked and came to a realization, not sure if he has realized it but using twitter as your text messaging is brilliant.....
Phil Haack (haacked):
If you are with @shiftkey tell him we're waiting for him outside the lobby of the Hyatt by the valet!
Suppose @shiftkey doesn't check his messages often, but his buddies with him do, if they follow haacked they may see that message and relay it to him, its like being able to get someone's attention without having to explicitly text him and friends, one message and you're done. I really like the idea, my only issue with twitter still is privacy, of course I've heard rumors of people tracking others inline presence to determine if they're home or not (for nefarious purposes) aside from that hiccup its a really useful tool for that. Of course if you don't know shiftkey and you most definitely aren't at the hotel this is just noise, which makes me wonder, would location aware tweets make sense? You only see a tweet like that if you're within x miles of said location/person?
Just some thoughts!