Thanks to Loudmouthman for tweeting about The Campaign For Real Blogs - Turn off the A list in May
I particularly like the Twitter mobile site which works beautifully from my Windows (or any other decent) mobile phone.
For me the reason Twitter is interesting is that I can listen to ("follow" in Twitter parlance) people I find interesting and receive their (max) 140 character micro blog posts and conversely they can follow me. Some people (referred to as "the a-list" in the post referred to by loudmouthman) follow thousands of people - there's no way they can establish meaningful relationships/conversations with that many people! Presumably they use automated tools to sort the wheat from the chaff.
Note: I use it for business (to forge working relationships and keep up to date with what's going on) and socially.
Where do I find the time? Well I spend even less time on email and hardly use Facebook any more. I still like the group membership (and notifications of changes) in Facebook.