Originally Posted by MaDalton

there's one thing that would be very efficient: if the site owner would have to prove that he has the license to use the content instead of the content owner having to prove that he owns the content and the site owner has no license - see the whole DMCA process.

up to now everyone can use content, pretend it's user uploaded, and then the content owner has to spend time and effort to prove his rights. if a site owner would be bombarded with requests to prove his legal usage of content he would be much more careful what he would put up.