Twitter is a SMS-oriented messaging service that allows one to make a group of friends you can send a single message to all at once they can get on their phone or computer. It’s become quite popular with geeky folk, almost to an unweildy degree, but if you keep your circle of friends small, it’s quite convenient.

If you are a globo-cultural voyarist like myself, then you’ll get hooked on Twittervision, an ajaxy Maps/Twitter mashup, where a world map keeps moving around to show the message and locale of the most recent public twitterer. Congrats to David Troy for making such a nifty engaging app out of public data.

The Twitter makers have done a great job making easy APIs to access all the public data going thru their service. There are tons of great 3rd party apps and even a wiki to keep track of it all.

You won’t be surprised to hear I learned about this from a twitter a friend, Andy Kaufman, sent out.