I've long been of the opinion that Twitter is completely useless to anybody who isn't afflicted with ADHD. The microblogging service's limit of 140 characters per post is ill-suited to anybody who communicates in complete sentences and who has thoughts more complex than "OMG this traffic is awful" or "I like turtles LOL".
My antipathy toward Twitter has softened somewhat as I've seen the use made of it by anti-Ahmadinejad partisans in Iran. The #IranElection channel (is that the right word for it?) has been, bar none, the best source for raw information on the protests and the government's reaction.
I've come to the conclusion that Twitter is ideally suited for this kind of hit-and-run reporting (an apt term in this case, since many of the Tweeters are running for cover as they post). In other words, Twitter does "live blogging" better than blogs do.
Twitter appears to recognize that they're a part of history today. Australia's News.com reports that the service has postponed a scheduled outage so the #IranElection channel won't be disrupted.
To Twitter: SALUTE! To those in Iran wishing to be free from Mad Mahmoud: I wish you success, with little or no bloodshed.
P.S. I still think the other 99.9% of posts on Twitter are completely useless. And I'll keep saying so until I start my own feed there.