San Francisco - Snocap, the digital music licensing and distribution service launched by Napster creator Shawn Fanning, on Tuesday announced the launch of a public beta test for a new, collaborative online mixtape service called BoomShuffle. The free service lets users create up to 15-song online mixes from Snocap's registry of more than 6 million tracks, and invite friends to collaborate by adding their own songs to the mix. The company will offer a BoomShuffle widget that can be posted on social network profiles, blogs and other websites.