I know, I know, stop the presses: Facebook is the most popular app on Android. The statistical wizards at Nielsen
reached this conclusion based on active usage, not total downloads, noting that the recently-updated Facebook app
has the most penetration across all of Android's user groups after the Android Market itself. The fact is at least a little surprising, since Facebook beat out Google's entrenched apps like Search, Gmail and Google Maps, which all had slightly lower user groups in every category.