The interesting thing is that it could be all sorts of things, chat room replacement being just one of them. However, as the article says, they keep disabling the features that make it special, so eventually it is going to fail.

Twitter is best understood as a "human-powered rss feed". You subscribe to a few people and you watch the river of links pouring constantly. Twitter can easily keep people connected with their environment.

I do see value in Twitter even if it is solely through Twhirl and FriendFeed.

As Matt mentions Twhirl is a beautiful application. I do not have any followers at Twitter (frankly there would no need since I only updated twice in the last 1 and 1/2 years save 100 updates a year ago from a RSS to SMS app I was having cooked by a friend), but I do follow about 13 key players and I love it when the little Twhirl screen pops up with a fresh title and a link.