You're missing friends on Twitter. I use it a lot because a lot of my friends are there; it's sort of like an asynchronous semi-public IRC channel where I decide who's in it. They, and whatever random thoughts they happen to feel like broadcasting on Twitter, are the "content".

It's a social network. If you're not being social it's pretty goddamn boring.

It's not without its flaws - nuanced, lengthy discourse is pretty much impossible thanks to that 140-character limit - but it's been a great way to keep up with my friends on an informal basis.