You see, the Digital Millennium Copyright Act (DMCA) requires such awareness for service providers like YouTube to be guilty of copyright infringement, and that safe harbor provision was the grounds for YouTube's victory on summary judgment. Furthermore, to succeed on summary judgment, YouTube had to prove that no reasonable jury could find that it knew of any infringing activity. While the lower court felt that YouTube carried that burden, the appeals judge disagreed, and has remanded the case back down for the District Court to determine if YouTube knew about or willfully ignored the infringement. What does this mean? All we can say for sure is that it'll expend more judicial resources and make more money for the attorneys involved. The result could very well end up, once again, in YouTube's favor, but we'll have to wait and see.