The announcement of Android's 10 billionth app download should be great news for developers. After all, more downloads means more money, right? Actually, it might not. High download rates are actually one of the reasons Android app developers may make less money than their Apple counterparts.

A September study found that Apple's developers make more money than Android developers because of Android's piracy problems. Apple has strict guidelines that require developers to go through a rigorous approval process and rely only on Apple tools, while Android is a much more of an open market for developers. That can also make it a playground for pirates. About a third of Android developers said piracy had cost them around $10,000 in revenue. Another 32 percent said it increased their support costs. And another quarter reported increased server costs due to heavy loads imposed by pirated copies

Even with the promising new Android figures, there are many more iPhone app downloads. The latest Apple figures from October 2011 (released before the mega-success of the iPhone 4S) reported 18 billion downloads, nearly double what Android reported today. Sure, Android is catching up with Apple, as AllThingsD's John Paczkowski points out, but Android has more free apps than Apple, according to a March 2011 report. That means Android users are more accustomed to freebies, making it harder for those trying to make money off of fee-based apps.