While most iPhone game players are used to the technique of downloading other apps in order to receive free premium currency in your current game (the examples are too numerous to count, but include games like the mobile version of Social City, which gives you free City Bucks for downloading both free and paid apps), Apple hasn't taken too kindly to the "feature," and has now started the cutoff process for apps that employ such features.
To be specific, if you wanted to earn free City Bucks in Social City, all you'd have to do is download other iPhone applications, such as Zynga Poker (ironically enough), Pretty Pet Salon, Living Social, and so on, as seen at the picture at right. You'd receive any number of City Bucks from each app downloaded, with more free currency being given out if you actually purchased one of these "sponsored" apps. While this is great for the game player, as they are allowed to further their own experience and purchase new items otherwise unavailable to them, it does create a very weird imbalance on Apple's top app charts, as apps that may suffer from bugs, or simply aren't that enjoyable suddenly rise to the top of the free or paid app charts. This "padding" makes other games (those that don't use this incentive-based download feature) look worse by comparison, which Apple claims simply isn't fair.