Thread:LegalizeAnythingMuppets/@comment-4807601-20131117102538/@comment-2256018-20131214162232

It means that copyright infringement is the use of works under copyright, infringing the copyright holder's exclusive rights, such as the right to reproduce, distribute, display or perform the copyrighted work, or to make derivative works, without permission from the copyright holder, which is typically a publisher or other business representing or assigned by the work's creator.

I'm not really a YouTube expert, but I did saw many videos before they got taken down on that site.