Apple has now banned "incentivized app installs" in which a player of a particular game needs to install another app to continue playing the original game. Also banned is "offer walls" in which a game player participates in an offer in order to receive currency related to the original game being played. The reason for the ban is to prevent misleading rankings as games are downloaded just for the in-game currency. This allows certain games to climb up the iTunes rankings, but not by legitimate means. A game that moves up the rankings snares a lot of attention and results in higher sales to the developers.
Many young children have been scammed by "in-app payments" to the tune of hundreds and thousands of dollars. In these cases, the child is playing a game and is told that he or she needs to purchase special currency to buy weapons with special powers, as an example. The child might be using his Dad's smartphone and simply makes the purchase without his parent's knowledge until the bill arrives with a huge surprise for Pop.
If one statistic says it all, it is that while "apps with in-app purchases still constitute a tiny minority within the App Store, they take a disproportionate share of the downloads." In other words, games with in-app-purchasing account for just 10% of all games in the App Store but account for nearly 40% of all games downloaded.
With Apple banning the incentivized app installs and the "offer walls", some analysts now see the App Store as being at a disadvantage to the Android Market. According to a report, "The 39.9 million downloads of free iPhone games in the US may slow until further notice as many of the incentivized install marketing campaigns have now stopped. The revenue growth of games using in-app purchases may slow for now. This change may help to further swing momentum in Android Market’s favor. A database created by Xyologic already indicates that last month 28,963 new apps debuted in Android Market while 18,787 made it into Apple’s App Store last month."