This is need, being that I am a heavy Twitter user. Google released a labs product named Follower Finder. What does it do?
Google Follow Finder analyzes public social graph information (following and follower lists) on Twitter to find people you might want to follow. We suggest two types of social connections: users with similar follow lists, and other users you may be interested in following.
For my profile on Twitter, which is @rustybrick, here is my analysis:
Seems about right…