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Monthly Archives: May 2009

The early days

Since the early days of the iTunes App Store, there has always been a free-to-paid loophole in the popularity ranking algorithms that allowed paid applications to appear to be more popular than they were.  When the App Store first opened, developers could send their apps to the top of the top-100 list by gathering sales as a free app and then changing their app to a paid app.  All of their sales as a free app, which were typically 10x-20x of what they would have received as a paid app, were included in their total sales. The top 100 list was created based off of total sales. Apple initially corrected the list manually, but eventually the use of this loophole become so prevalent that Apple had to change their popularity algorithm.

Separate Paid and Free Top 100 Category Lists

In December of 2008, Apple reorganized the App Store and created separate top paid and top free lists for each category. This reduced the incentive to use free app sales to increase popularity. However, it did not eliminate it. During searches for apps, the popularity meter would still show popularity based on free app sales. This is a good time to mention that the top-100 popularity algorithm is different than the algorithm for the popularity meter that shows up when searching with iTunes. Without going into details, the top-100 popularity algorithm gives a much higher weighting to recent sales. This allows new applications to more easily break into the top-100. However, it is not entirely based on recent sales, and that allows apps that had a boost of popularity to remain on the list longer than their current sales would otherwise allow. The popularity meter does give some additional weighting to recent sales, but much, much less.

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