WhoTweetedMe will not only show you how popular your tweets are, it will help you find influential people interested in the same topics as you. (That means if you follow them they are more likely to follow you back, since you share the same interests.)
How it does that is by showing you how many retweets any link got and when, and by showing you the potential reach and follower count of each person retweeting the post. So all you have to do is teview the reach and follower numbers to find the top people for any topic.
Cool Feature: Top 20 people tweeting a link are listed, so if you are tracking a link you tweeted, you can thank them right there with just one click!