Apple appears to be making changes to its App Store ranking system in order to de-emphasize the number of times an app has been downloaded.



From Ars Technica:

The move is suspected to be in response to app publishers using "pay to install" promotions to get users downloading their apps in large numbers, therefore letting those apps artificially climb the rankings. In some cases, those apps might even be facing an App Store rejection.

The "pay to install" model works like this. An app publisher might offer several different games on the App Store, and that publisher might utilize a promotion or ad network to advertise their apps, but with a twist. In many cases, users can "purchase" in-app goods or points for their favorite game by downloading another app by the same publisher. This allows the user to get "free" goods to use within the game, while the publisher's other apps bubble up to the top of the App Store rankings thanks to the sheer number of downloads.

  Apple cleaning up App Store rankings by de-emphasizing downloads