Twitter on, you twit... ?

OK, do you Twitter?

I don't know why I signed up but it seemed new and cool but not TOO popular... Now, of course, it's being advertized EVERYWHERE for EVERYTHING lately...and, well, I don't really get it. People have entire conversations on twitter. I'm not sure how, really. I've aimed comments at a few people (mostly people Todd knows) but I wouldn't say I engage in actual conversations. So, what's the appeal? What am I missing? I must admit that I just find it to be a random update-stream of consciousness-Facebook status type thingy. When I'm really feeling random or really, really, really need to vent (but I can't on FB because it's about someone who may or may not see my vent on there) then I turn to Twitter. But I feel like a 'twit', really, because I feel like all these people are using Twitter for something more interesting and engaging than I'm using it for. What gives?

So -- fill me in on what I'm missing out on. Until then, I'll continue to randomly vent on and on... ;)