Don't confuse the reason something is made, and how people actually use it. Just because the original purpose of Twitter was a bit humble doesn't mean that it stays that way with millions of users. It's currently the best marketing tool available (if you are interesting) and search.twitter.com is the zeitgeist of the whole world. It's not about you. And if you are a narcissist then the existence of Twitter is not going to make you more or less of one. It might make you a more visible narcissist, but fundamentally people are going to be who they are, offline or not.

Thanks for the tip! I'm checking out Eventful, it seems really cool. We're going to be playing a lot this summer, so it's possible we'll get near there. And we are on twitter, http://twitter.com/lunchmoneymusic.