Streaming music powerhouse Spotify has expanded its free mobile radio service onto the Android platform.

The ad-supported radio app debuted on iOS in June; Desktop Spotify users have had access since December.

Available for free via Google Play, the Android app lets users create stations based on an artist, album, or playlist, and note whether they like a song or don't want to hear it again.

Spotify founder Daniel Ek--an Inc. 30 Under 30 honoree--brought the company to the U.S. in July 2011 through a deal with Warner Music. One of Europe's largest music sites, the 6-year-old service has seen exponential growth in the U.S.

Spotify now has more than 15 million active users and more than 4 million listeners on paid subscriptions, reports Tech Crunch. In September 2011 Spotify had 2 million paid subscribers, the site notes.