Picked up Jason Kottke's thoughts on Twitter from Gruber, but for me, I thought the interesting part of Jason's remarks came after the bit John quoted.

For people with little time, Twitter functions like an extremely stripped-down version of MySpace. Instead of customized pages, animated badges, custom music, top 8 friends, and all that crap, Twitter is just-the-facts-ma'am: where are my friends and what are they up to?

Twitter's like Flickr without the images.

When one thing (i.e. Twitter) is easier than something else (i.e. blogging) and offers almost the same benefits, people will use it. I have a MySpace account, but I rarely use it. I'm certain part of that is age-related, but the other bit is that I already have my own blog, on my own domain, so why do I need to reinvent the wheel over on MySpace? (Other than the juvenile reason of not wanting anyone else to have "myspace.com/retrophisch", I'm hard-pressed to explain why I even bothered.) But there are bits of life's detritus that I don't feel like going through the trouble of blogging, and I think my Twitter account is a great place for those to accumulate, and it's a heck of a lot easier, as Kottke points out, than either blogging or MySpace.