A couple of days ago Twttr launched. I have been playing with it a bunch. There are some similar services out there but this one is pretty cool because of their use of shortcodes and there is a public area where you can see the overall flow of posts through SMS that is broadcast out to others. People who are your friends essentially subscribe to your messages and whenever you update them, all your friends get the update. It's very bloglike in my opinion in that it is subscription based pull messaging. I like how they have put the pieces together but wonder how you avoid it becoming spammy.
The bigger question to me is how this fits in with Odeo. It appears that a number of the Odeo team are working on this which makes one wonder what's going on with Odeo?