years ago i wrote a screed about how Google/Youtube essentially won the video sharing site war by strongarming the majors into licensing deals. Early on the other sites were getting DMCA'd by rights holders. Youtube scaled biggest fastest with users uploading tons of TV shows and music videos.

Youtube said "it's too hard to chase down the copyright infringements, but if you license with us, we will give you adshare revenue and build technology (eventually) that can identify them all."