I'm a bit conflicted about Twitter. It seems like unalloyed narcissism. But then, I've been giving it a try for the last week or two and I've noticed that it comes in handy for odd one-liners that I might have turned into blog posts but which really don't deserve that much air time.
So in that way it's potentially useful, provided one doesn't become unhealthily obsessed with apprising the internet of their every eye-twitch.
There's a per-tweet entry limit of about 140 characters (160?) and I often wonder how this will affect the next generation of upper-academia: how much do you want to bet some first-year university student will some day print off a week's worth of tweets and submit it as her writing assignment? God help us all.