Android App Store, Statistics.
Apple is tendentially silent if it comes to numbers. They usually offer broad totals but neglect to give detailed insights into the actual distribution and structure of these numbers. This isn't much of a problem with most of their products. Sure, it'd be nice to actually know just how the Mac Mini sells, but it's not important information. The App Store, however, is different. People who develop software for iPhone or iPod touch invest time and money into a specific application. The more these developers know about their target audience, the better. It's much easier to develop good selling software, if one knows what the potential buyers might like. There're different ways of gathering this information. One has always been sale statistics. Knowing which product did well helps tremendously in figuring out what people might like. But since Apple doesn't offer this information with the App Store, people had to rely on estimates, as a substitute. Now Google released just these numbers for their Android App Store. And although it just got online, they still offer a good insight into the potential interests of buyers. The demographics and segments might differ, but I still think it should be a good starting point.