The Facebook Unfriend Finder has been downloaded 44 million times since it's release and it adds a little "Unfriends" section to your profile, showing who has dropped you from their friends list. It also shows you who has declined your friend request, and even puts a little red counter of total "unfriends" in your menu bar, just to make you feel extra shitty. So i believe this Apps will show you how uncool you have been over time.
Source: http://www.gidilinks.com/