While Google's been working feverishly to build out its Play Store, bringing it to other countries and expanding its offerings, the company's music store has been lacking one crucial feature that its competitors have: library matching. Where Amazon and iTunes can scan your current collection and add the songs to your online storage, Google has, until recently, required users to upload every individual track manually. A long and tedious process. In mid-November, the scan and match feature came out for Europe, and today it arrives for US residents.