Yeah, the word "automatically" does a lot of heavy lifting there. But like others said, it's crowsourced. You watch a video, tag it, done. There's some anti abu

Yeah, the word "automatically" does a lot of heavy lifting there. But like others said, it's crowsourced. You watch a video, tag it, done. There's some anti abuse tools, like tags done by new users being served not all the time and tested by other users before it's trusted. I have never seen bad section tagging over the past two years.