The videos were flagged and reviewed as acceptable several times, then subsequently flagged and reviewed as unacceptable. The inability to prevent scripted attacks like this where an attacker brute forces takedown requests doesn't strike me as "doing their best".
They can defend against DDoS attacks, why can't they do better against fraudulent takedown requests? I think the answer lies in their monopoly status and the fact that creators don't have many other options for getting real traffic outside of YouTube.
They can defend against DDoS attacks, why can't they do better against fraudulent takedown requests? I think the answer lies in their monopoly status and the fact that creators don't have many other options for getting real traffic outside of YouTube.