What's the deal with Twitter?

I stumbled upon this blog via a friend's Twitter feed.  I haven't quite digested all of it yet, but these posts on Twitter strike me as being roughly accurate.  Maybe my environment--Twitter-happy Washington--makes me sympathetic/adhere to Twitter, maybe my upbringing (AIM, Gmail, and Facebook status updates) attract me to it, but either way, I think it's an enjoyable--and potentially useful--medium.