Always astute Jerry Michalski sends along a link to a very nice description of why Twitter is useful. Although I am still learning about this tool, I am becoming a convert to its ability to help me connect. It still has rough edges when used alone in not being able to control the amount of information you get, but I am also experimenting with utilities like Tweetdeck to help with that. Also a comparison to a competitive client Twhirl.
Biggest negative is that many professional contacts are still not onboard, limiting its connectivity. These people are on Linkedin, which also has a 'what are you doing now' function, but it is little used, and it is not the main focus of Linkedin. Meanwhile, Twitter does not have the infrastructure for professional information that Linkedin has.