Refollow is a nifty little utility to help you manage your following and your followers on Twitter. You can sort by picture or no picture, following or not, and even tweets in the last x number of days.
If you use Twitter you should check it out.
If you don't use Twitter, and before you ask me about why I want to tell the whole interwebz about what I am eating for breakfast let me point you to a presentation that I worked on illustration the benefits of Twitter. (http://www.slideshare.net/freshconsulting/what-is-twitter-1689136)