I think they use sectioned hashes for that sort of thing. They certainly do for eg ISIS videos, see https://blogs.microsoft.com/on-the-issues/2017/12/04/faceboo

I think they use sectioned hashes for that sort of thing. They certainly do for eg ISIS videos, see https://blogs.microsoft.com/on-the-issues/2017/12/04/facebook-microsoft-twitter-and-youtube-provide-update-on-global-internet-forum-to-counter-terrorism/ https://blogs.microsoft.com/on-the-issues/2017/12/04/faceboo...