Here is a nice web app for Twitter built by Alexander Taub and Michael Schonfeld. It’s very simple and straight forward, asking “who’s your MVF” – most valuable follower. You login via Twitter and authorise the app to dig around in your follower list, and after a few moments it tells you which of your followers has the largest following. OK, so it’s not necessarily your most valuable, but your most popular – even still, it’s an interesting question to ask of any audience.
Mine is @ONECampaign. Who is yours? Find out here.