Unfriendio sifts through data that Facebook makes available through its API and produces a ranking of how active your friends are. To begin, click the "Launch Unfriendio" button. You will be prompted to login through Facebook.
Unfriendio is a first party app. This means that your data will never pass through my servers. So don't worry: I will never process or look at your data. Your browser will be talking to Facebook directly.