According to some eagle-eyed folks, the change not only affected Top Grossing charts for the App Store, but Top Grossing charts across all App Store categories. It seems that the change favored paid apps over those that emphasize in-app purchases, with apps that have consistently ranked near the top replaced by more obscure paid apps, like a test kit for United Kingdom drivers and a $15 translator app.
As for why this algorithm shift occurred, some posit that Apple wants to put more significance on paid apps and less on apps with a recurring subscription revenue. Given how games like Clash Royale have been on Top Grossing charts for quite some time, the change allows Apple to spice up the lists and not have them be so static. More significantly, the shift allowed paid apps to compete on equal terms with subscription-based ones, since the latter’s lack of any upfront cost give them a leg-up over paid apps.
The algorithm change helped give some of these apps the exposure their developers probably wanted, but things went back to normal at the stroke of midnight on Monday. Even so, this gives us a hint as to what Apple might do in the future with the App Store, perhaps as a means to improve app discovery.
