I think the people who are using it are focusing on conversation. Like, you put something out there in 140 characters or less - "should I drink this beer here?" - and your contacts all chime in (in 140 characters or less) on what you should do. Or, "I have seen this thing on the internet - [link]" and then everybody chats about it. Sorry, 'tweets' about it.
In that way it appeals to what I enjoy about the internet - finding stuff, sharing it and talking about it. But
www.friendfeed.com does that much better, aggregating your web stuff and providing much more room and context for discussion. If you have Facebook, you'll notice that the new Facebook design leans heavily on Friendfeed, and its discursive qualities. This is a thing I like.
It's worth noting that Twitter gained a lot of notice as it launched just before some technology conference and everyone at that conference went nuts for it. It seems to have ridden that initial burst of interest ever since.
So, crap when used for posting "I'm at the supermarket!" "I'm outside the supermarket!"; waffles for using it for conversations; waffles taken off because that is done better elsewhere.
Crap.