Still-in-beta interactive music startup Turntable.fm has taken another step toward going mainstream Tuesday. It has just become licensed by ASCAP (American Society of Composers, Authors and Publishers), a performing rights organization which licenses and collects royalties for performances.

Turntable.fm has been taking the web by storm of late, amassing around 300,000 users and more than its share of buzz. However, many have wondered if the site is wholly legal. Basically, it's a series of musical chatrooms in which five DJs can spin tracks on demand via Medianet or by uploading their own music. The site even shut down international usage recently in an effort to stay Digital Millennium Copyright Act (DMCA)-compliant (the DMCA is U.S.-only).

Still, myriad musicians (and music industry types) have flocked to the site, and we have yet to see any significant backlash against it. However, Turntable.fm is still in beta and is invite-only (if you have a Facebook friend on there, though, you can get access), so it's still a bit under the radar in the mainstream sphere.

The fact that the site is still in its infancy makes the ASCAP license an interesting milestone (Spotify secured its license when it launched in the U.S. last week). "It's great to see a tech start-up securing an ASCAP license from the outset, ensuring that songwriters, composers and publishers will be paid fairly if the site succeeds," said Jon Bahr, director of marketing for ASCAP, in a statement.

Perhaps we could be seeing Turntable.fm coming out of beta soon.

We've contacted the team for comment.