Ask HN: What drove SoundHound Android so many installs?

Really cool stuff SoundHound is doing but I was curious about their Android app.

Looking at http://i.minus.com/ioLUSWTerE1zz.png

See how the Android Installs plateaued last month, I'm curious as to what drove it to go up so high, and we can also see how it dropped flat afterwards.

Thanks