Yeah, but then Youtube thinks, "He hates that channel!", rather than, "He doesn't want to rewatch old videos."
I keep getting old furniture restoration videos in my feed. I've seen them already. How about different channels on the same topic with new videos posted?
When you select not interested, it gives the option of saying it's either because you already watched the video or that you don't like the channel. I don't know quite why they keep recommending videos I've watched recently, but at least telling YouTube I've seen a video (...) prevents it from spamming my recommendations.
It's quite a few clicks when you could just mentally skip over it, but indeed I wanted it to learn so I went through the trouble. Again and again. Probably more than a hundred times. It doesn't learn. I just pass over them now. The algorithm probably knows better than all of us what keeps us longer on the site anyway and the button is just a dummy.
Even without the category system, if the user never ever goes back to rewatch a video they've seen, it could perhaps realize that the user doesn't want to rewatch videos they've already seen. Or if some videos or channels have a very high re-watch rate and others don't (presumably music channels vs., say, a random furniture restoration channel), it could tune for that. Clearly they're not separating the types, and it's not because they're not capable.
That doesn’t solve the problem at all. I like and am interested in the videos I’ve watched. I want the algorithm to know I’m interested, I just don’t want it watch something I’ve watched again.
If you are not logged in you can't do this, for obvious algo manipulation reasons.