So is twitter worth the bother? Either way it's being increasingly blogged about, as Technorati's 30 day graph shows.
Yes, it's an instant blog. And yes, it can be irritating. And yes, if it was possible to select groups of friends to contact on a particular subject, rather than a general "everyone" then it might be much better.
Rival Jaiku, is getting a bit more attention at the moment too - but the young upstart could be Cerkle, though what you gain in terms of flexibility of contacts (you can nominate specific "cerkles" of friends to send your message too) you also gain in irritating complexity. To get the most out of it you also need to pay money (?!) and subscribe to their premium version and I think you can only pick up messages from the web - though you get a text when they arrive.
I wouldn't be surprised if Cerkle's business model fails, but its rivals (or even a new entrant) took the best of all these offerings: instant update, location mapping, and ability to choose groups of people rather than everyone, and cleaned up.