It’s passive interpersonal communication. You can know what your friends are doing, without even trying.
When I try to explain the logic behind Twitter, most people respond, "Why do you care?"
Because a simple text message or an IM notification is convenient. Sometimes I don’t really care what people are doing, but it only takes 5 seconds to read a tweet.
It’s really easy to update your status too. Just a simple SMS msg to 40404.
Twitter is all about the community, and right now, not many people use it. I have tried to turn people on to the idea, but few understand the concept. About 50% of my referrals are one and done. They update once, and never touch the site again. A small percentage of those people will update seldomly, and then something pulls them back to the site to update their status.
I guess I love Twitter because it’s so simple. There are other services like Jaiku, which have the same foundation, but they are too complicated. Do you think Twitter will be around in five years?