Well, I don't use twitter myself, so my perception of it might be unclear, but it seems to be a great platform for celebrities and pseudo celebrities to argue with each other.Beyond that, what is there, really, that needs to be tweeted?
From what I've seen Twitter is great for powerful, dynamic people to read in tiny bursts and write in tiny bursts, then get on with what they were doing; the character limit makes Twitter the success it is. It also makes it fail at being a meaningful communication platform, given that concepts must be expressed in a finite, tiny space. Much Twitter anger seems to stem from a fundamental failure of one party to fully explain thier position within the character limit. But given celebrities' small attention spans and/or demands on thier time, I don't see them moving to another social network unless it makes the experience faster and easier to consume still. This makes Twitter-in my mind-less of a place for normal people to socialise, and more of a stream-of-consciousness of celebrities - a one-way social network, and occasional personal messaging client.
It's also great for bitching at big companies. They usually track twitter very well and I have even been fast tracked through customer service once because I tweeted that my telecom company was crap. The standard procedure if to get the complains off the web as fast as possible ;) It's also a great outlet when I'm simply frustrated. I have like 30 followers so I feel like I can post whatever my current corporate frustrations are.
That's Twitter in a nutshell - "for when you're too lazy to use PRNewswire."
