I've also heard from some friends of mine involved in marketing and web design that its a useful tool in building web traffic to particular sites. The general statistic I've heard thrown around is that for any link you post on your Twitter update, 4-10% of your followers will visit that site. In this sense, more followers is a good thing.
So an entrepreneur seeing an opportunity has developed a new service: TweepMe will get your "thousands of followers" (4,000+) automatically for a fee of $12.95. (By the way, they currently are offering $2 off on their service.)