Sometime in mid September, Google’s Android Market surpassed another milestone. The total number of app submissions surpassed the half-million mark, but there is a catch.

More than 37 percent of submissions have already been yanked from the market for various reasons. The vast majority of apps were free and they were apparently removed by their developers, who focused on paid versions instead. Of course some apps were removed simply because they were pants.

Apple’s App Store boasts more than 600,000 submissions, but it has also removed quite a few apps, about 24 percent. Of course, Apple exercises a bit more control over its developers and content, so comparing the App Store to the Android Market is a bit like comparing East Berlin to West Berlin.

By the end of Q3, Apple’s App Store carried 459,589 apps, while Android Market had 319,161. As for Redmond, the Windows Phone Marketplace currently carries about 35,000 apps.