Mutuality is a free Twitter tool that lets you mass unfollow or mass follow Twitter users. Mutuality is completely online, and free to use. You do not have to download or install anything.
Update (31-Aug-2012): This website is not available now.
To use Mutuality, you sign in with your Twitter username and password. Then, you can specify what you want Mutuality to do:
- Mass Unfollow: Mutuality will unfollow all those Twitter users who are not following you back.
- Mass Follow: Mutuality will follow all of your Twitter followers who you are not following.
Before Mass follow or unfollow, you can specify up to 50 Twitter users who you want to exclude from the follow/unfollow operation. Mutuality is pretty easy to use. For a more full featured Free Twitter follower management tool, try BuzzOm.
One limitation of Mutuality is that it works only on those Twitter accounts that have less than 1800 follows/followers. If you want to just mass unfollow, then you can use Tweetelity that does not suffers from this limitation.