Video and Copyright - YouTube

It's hard to understand why YouTube is such a big deal as there are hundreds of other free web-based video-hosting services. Yet despite its competitors, YouTube dominates the online world, streaming millions of videos everyday. And this led number of major media companies to explore the legal implications of the video site's unauthorized use of copyright material.
The good news for YouTube is that it stands on a much firmer legal ground than old Napster, thanks to a special provision in the Digital Millennium Copyright Act (DMCA). This safe harbor protection that the US Congress granted back in 1998 puts the burden on the copyright owner and the infringer, not the technology or service that allows for such material to be delivered or shared. The act grants online service providers immunity from monetary and injunctive relief if they are not aware that uploaded material is infringing, they remove infringing content immediately upon notification, and they do not receive direct financial benefit from the infringing material.
So basically, even if you find videos of Prison Break or Lost, YouTube would not be liable even if it's not proactive about taking down the material!