When a mobile app gets more than a hundred thousand downloads in its first few weeks, that is usually a good thing. Instagram hit 100,000 in a week, and music-sharing app Soundtracking got there in two weeks. But another music-sharing app, Play by AOL , is right up there with 250,000 downloads in three weeks. Play is very similar to Soundtracking. It lets you share snippets of songs, along with album art or photos, with your friends via Twitter, Facebook, or the in-app network. Play might even have more downloads than Soundtracking, which is getting far more buzz. But what's interesting about Play is that it launched first on Android, and is not yet available on the iPhone. Still, it's getting a decent amount of traction.