This is the Achiever App. We give you the possibility to track achievements across your Steam library.
Because you might be interested in "achievement hunting" just as I am, what stops you from having a companion in this adventure? This is the purpose of this app, track your achievements, tell you what needs to be done, clear your path to easier and faster achievement unlocking. If you are lucky, which you are, you might find some statistics to compare yourself to friends or to the world somewhere in the app.
This is really basic. Just make sure that your Steam account is public so that we have the permission to read from your library and achievements. Enter your SteamID and you are good to go.