At first I used to think its a waste of time bit then if you follow the right ppl, then its a really great place to get first hand news and explore new stuff. Apart from that its a good way to publicize your stuff.
I do have an account but I haven't been on it in a while. XD I tend to forget about tweeting things easily and then before I know it, it's been months since my last tweet. And then I forget the password and can't log on anymore, haha.
I think it's cool if you have a lo t of people to talk to on there frequently.