YouTube itself does no patrolling. It can't have actual knowledge of specific acts of infringement if it wants to be protected by the DMCA; it's by turning a bl

YouTube itself does no patrolling. It can't have actual knowledge of specific acts of infringement if it wants to be protected by the DMCA; it's by turning a blind eye to it that they gain legal immunity from the infringement. You can be aware it's happening somewhere (even a lot) as long as you're not aware of the specific instances. The media companies themselves do the patrolling and their actions, through a special dashboard YouTube provides them, result in the widespread takedowns you see. They can do their own flagging and also review potential matches by a ContentID-type system that checks uploads against signatures of files the media companies upload to claim as theirs.