A company has analyzed over 1 trillion in-app ad requests in Q4 of last year and according to their report, Clean Master was the most used application during that time for Android.

Interestingly, Clean Master's Security Antivirus AppLock application secured 2nd place during that time span as well. It's likely that Clean Master's deal with various OEMs to get the application preloaded onto their phones helped put the app in front of so many eyes.