According to a report from 9to5Mac, Apple has changed their App Store ranking algorithm. Apple system may no longer rely on just the number of downloads per day, but may now also adjust based on application usage.
The algorithm change became apparent when FaceBook swiftly moved into the number 1 position after previously having sat in the 10-20 range for quite some time. This would indicate that the algorithm is factoring in usage, as FaceBook is one of the most used apps.
Via 9to5Mac
