[RawAlex]

If Brad has a valid DMCA notice in his hands, he is obliged to act or become just about as responsible as the person violating the copyright. It isn't unusual for host to take this step, and in fact this is the best way for you to get quick resolution if your material is getting violated - DMCA the host, and they will normally take action (if they are in the US).

Where I think this may fall into a black hole is the idea of "tube sites whose business model relies predominately on revenues generated from the dissemination of obviously stolen content ". This "fact" could only be supported by valid DMCA noticed from the copyright holders, otherwise Mojohost has no way to determine the validity of the content, and have no reason to act without notification. Shutting a site down and then finding out all the content was used with permission would be a huge legal nightmare.

I look forward to a lawyer's opinion on this one!