Refynr is a much better tool http://refynr.com/. It works on Twitter as well as Facebook and you have much more granular control of what to include or not include.
Apologize in advance for the autorun video he has added to his home page ;<(.
Despite what you might think, unlike Facebook, people do not really give a damn if you unfollow them on Twitter. Stop being such a wuss and just unfollow people whose tweets you don't want to see. If they're the rare case who gets back to you and asks you why, you can then provide them with valuable feedback.
Actually no. People do. Heck I even wrote a simple ruby script to help me track when and what I said that caused people to unfollow me, and who it was to see if they important or not:
The real solution came with lists. Following has always been a vanity thing. There are people that I want to follow but don't want those people to know. Also I want to follow people out of respect but their volume is too high. Private lists give me that solution.