This service may be helpful for the Twitter compulsive copied from the website of Twitoria:
“Clutter is pervasive. Twitoria tries to reduce Twitter‘s clutter by revealing friends you are following that haven’t posted an update in a while. It can, for example, easily track down those pesky friend spammers that post no content, or people that have abandoned Twitter for another status updating service. Why follow them if they no longer tweet?…”
Twitoria © 2009
Comic: (Unshelved)
I don’t mind keeping inactive people but I hate keeping people who are not following me or people who spam tweets. It’s better to unfollow them who are not following you or do tweetspam.