It's the new thing. If you're still not "getting" Twitter, which I wasn't... up until a few weeks ago, wrap your mind around this:
This is worth a read, BTW. He talks about how using social media tools can turn *into* a strategy.
Useful Links for Twittering
Why short is tweet for the blogging community by Jeff Jarvis for The Guardian (Feb. 25, 2008)
Twitteroo (URL shortening)