Twitter: Whats the Appeal?

I know a lot of people that use twitter... and I'm always left wondering, Whats the Point? Twitter is a form of microblogging thats like having a giant conversation with all your "Friends" at once.

I dont really understand why people bother. Chances are, if you want to interact with these people you'll already be reading their blogs, chatting to them over IM, sending them email, talking to them in person, talking to them on the phone, interacting with them via facebook, myspace or other social networks.

Do we really need another way to communicate with our "Friends"?