With user numbers in the 10s of millions, the impact of Twitter's influence is remarkable. As I mentioned before, its new suggested users list is a great way to find new and interesting content, but here's an even easier way to find and follow your favorite celebs. Twitter maintains a list of 500 verified accounts, from entertainment celebs to musicians to olympians.
Twitter uses verified accounts to "establish authenticity with people who deal with impersonation or identity confusion on a regular basis." The feature is still only in beta, so there are more famous names on Twitter than there are verified accounts. The special verified badge can come only from Twitter, though, so if an account features it, you know it's the real deal.