The author misses that the different parties have different goals. TapTapTap wants to maximize app revenue. To do that, you do want to sort by revenue. (Actuall

The author misses that the different parties have different goals. TapTapTap wants to maximize app revenue. To do that, you do want to sort by revenue. (Actually, probably something like revenue per last n impressions, so that apps that have a traffic spike won't stay up there when the spike is over.) But Apple makes most their money off the sale of iPhones. So they want people to be happy when they use the app store, even if it doesn't make them as much money directly. When someone downloads and enjoys a free app, that's meaningless to TapTapTap, but it's great for Apple. You can't exactly measure user enjoyment, but it's not unreasonable to suppose that "number of downloads" is a better proxy for user happiness than "net revenue".