Oopppss, Sorry this service has been discontinued by the website owners. An alternative to Mass Unfollow People can be found here: Unfollow Everyone – Please be careful when using this service as this will unfollow everyone you are following. It will not filter anyone and you will have to start from the beginning. Think of it as “reformating” the people you are following. This is a good tool if you are following only people that you have no particular interest in.
Recently, I have seen some tweets from people asking if there was a way to mass unfollow people who you are following and not following you back on Twitter. Although I do not recommend that you do this, there is an online application that can mass unfollow on Twitter for you.
Before you attempt in using this tool, let me explain my reason why I think you should not automatically mass unfollow. If you are like me, I follow people that is of interest to me and I do not care whether they follow me or not. In this case, if you use this tool, you might accidentally unfollow everyone who is not following you back. Now if you really want to bulk unfollow people, then
Mutuality is the right tool for you. Mutuality is a free simple service allows you to bulk unfollow people not following you. You are allowed to use it only three times and after that, I really do not know. The developer has not given more details about this service.
If you have less than 5000 followers, my suggestion to bulk unfollow people who do not follow you back is Twitter Karma.
Another interesting tool to find out Who are you following that’s not following you back or Who’s following you that you’re not following back is Friend or Follow. This allows you to individually unfollow or follow people on Twitter.
UPDATE July 2010: Due to Twitter’s API TOS, the above service may or may not have been banned. If the service still exist, it is like that some features have been disabled. One such feature is “Mass Following and Unfollwing On Twitter“. Please refer to this post.