On HackerFollow (http://hackerfollow.com), we created a leaderboard of most-followed users. There's also a bookmarklet for when you're on a user profile to add them.

This seems like a pretty similar service. Love the market validation ;)

Current leaderboard:

AndrewWarner bdittmer davemc500hats dcurtis dhh erickerr gyardley keysersosa kn0thing loganfrederick mojombo paul pg treblig