Like it or not, the Android Market has always been treated as kind of a younger, more awkward sibling to Apple‘s App Store, at least in the press. But now, it seems like little brother is really growing up — since its inception, the Market has dished out about 10 billion apps, with more than a billion being downloaded each month. (Apple watchers may note that this is the same monthly traffic the company boasted at its iPhone 4S press event.)

This is a momentous occasion for the Android Market, one that Google is celebrating with a 10 cent sale. The Market served up its first billion Android apps over a period of 20 months, but the second billion only took five months. And now look at it — it’s hitting the billion threshold on a monthly basis. Sure, maybe it still hasn’t caught up to the App Store, with its 18 billion total downloads, but it’s definitely no slouch. And, in terms of applications available, this doesn’t necessarily reflect true app usage. There are still plenty of Android users who sideload or download applications from other sources.

Where did your favorite Android apps come from? Are you a Market addict, or do you usually download from other sites?

[via Wall Street Journal/AllThingsD]