Inspired by: I Nuked My Twitter Feed And You Should Too - BuzzFeed News (buzzfeed.com)
Another example: http://tweepi.com/app/#!/manage/cleanup
So, you’re following more than a hundred people on Twitter. You must have noticed that many of these users do not engage in conversations, never retweet anybody, or simply just ramble about nonsense stuff all day long (no links to useful content whatsoever!). You can use Tweepi’s cleanup tool to filter these people out and unfollow them.