Fresh off a court victory against Google's YouTube, ASCAP tells us it is setting its sights on users of the video-sharing site. Welcome to the exciting world of copyright licensing, blogger; you may already owe gobs of money!

ASCAP licenses the performance rights for music, collecting royalties for its songwriter members when their songs are played in certain contexts.

Those contexts now include a YouTube video embedded on your blog or website, assuming your site is not "purely" non-commercial and is deemed large enough by ASCAP. The group just sent a collection letter to internet entrepreneur Jason Calacanis (pictured) for YouTube videos embedded on his Mahalo reference site. Based on what the group told Valleywag, other startups should be worried:

ASCAP does not offer licenses to – or require licenses from – those who simply make their personal blogs available on purely noncommercial Web sites. Mahalo.com is a larger venture than simply a personal blog, and therefore ASCAP is engaged in discussions with Mr. Calacanis concerning the use of ASCAP members' music on the site.

ASCAP sent collection letters to other website owners in the spring; YouTube told recipients to refer the group back to YouTube. But then a judge ruled Google owed ASCAP $1.6 million while a court fight between the two sides over licensing drags on. At some point, website owners are going to start wondering how much longer Google will offer to handle all the legal complaints over YouTube embeds — and just how many songs they've embedded over the years and now owe royalties on.

(Pic: by David Sifry)