Well Bitshares Music will be the back end of websites running on top of it.
The pandora/8track/groveshark-ish website that allows you to create a profile and upload your songs will have a few mecanisms in place to garantee that a song (and all the songshares) was uploaded by the correct artist / band / record label.
You have the market for starters. People will not invest in a song that could just get ignored once the real celine dion tweets that Mario69 is not the one singing in my_heart_will_go_on.mp3
So the market/investors will want to make sure they are putting their cash in the place that will produce the most ROI.
Second is the Flag/report button. This could make the jukebox ignore the song and skip it, until the issue is resolved.
Third you could have a "verified account / profile". So when the song has a green check next to it, it's because the uploader proved that he or she is the content creator (or the record company that has the rights to Beach Boys - Surfing USA)
Does this make sense?