The problem I find with it is that if you follow more than a handful of active tweeters, then there are too many tweets to read in a reasonable amount of time. That said, I find I get useful information from people with similar (work-related) interests to mine, and a way to 'get to know' people, which can lead to more in-depth conversations when you have something you want to converse about. (twitter.com/billroberts)