Launched at SXSW , social music app SoundTracking has announced its quarter of a million milestone today, surpassing 250K downloads in just six weeks after launch. Jang loosely calls SoundTracking the "the second fastest -rowing social sharing app on iOS without any legacy website or mobile apps to drive installs from," comparing it to photo-sharing app Instagram which we've highlighted as the first. Another music sharing app, Play by AOL , has also hit 250,000 downloads in half the time on Android. While Jang wouldn't disclose numbers of daily active users or users, he does tell me that over 50% of SoundTracking users are using the app to share their music moments into both Facebook and Twitter, which might explain the increased signups. It seems like every five minutes or so someone else is following the SoundTrack to my life.