I use it Neil. It's mad but compulsive. If you are following several people, their tweets are posted sequentially, so it is like reading the ramblings of a mad man.
I haven't got anything out of it, apart from the opportunity to waste a bit of time in a fun way.
I've just started using it but not sure if I like it or not. One of my clients has written an article about using it for marketing which you can download here.