Twitter is an opt-in version of IRC. Think about that for a second. Now imagine the IRC chat room has people you respect (for me Charlie Brooker, Stephen Fry and Martin Fowler), and you can hear their thoughts. If there's anything we have learnt about the Internet over the last 2 years it's that stalking is at an all time high. It's also becoming mainstream.
I was very sceptical about Twitter. Seeing it as a way for people I sort of know spamming me with fascinating anecdotes about getting pished with their mates the other night. But it's quite simple, just keep it professional and only listen to people you know and/or respect. If your life is all about High School Musical then you can listen to the ramblings of the stars from the show. If you are deeply into software development, then all of your heroes are already on board.
I think to get the most out of Twitter you need to either have the iPhone/Android/Blackberry application, or not have it unblocked at your work. But it really is a genuinely interesting new source of information I check multiple times a day along with my SMS, email and rss feeds. I feel more connected and as the circulation figures for gossip magazines will tell you, people love being a little too intimate.
Feel free to follow me!