Earlier quoted context omitted.
> show people what they like to see? The thing is, "what people enjoy while watching", "what they derive lasting benefit, memory or happiness from", and "what they click on in a thumbnail" are three different things, and youtube optimizes for the latter. Which is why youtube face is a thing.
Click-through rates are indeed very important, but that's not all they optimize for. They are also looking at watch time, what you do after watching the video (do you watch more videos from the same creator, or on the same subject, something totally different, or do you leave the site), whether you interact with the video by liking or commenting, channels you have subscribed to, things you have searched for, etc. And…
They must do this as a global level, not an individual level.
I've never noticed a single one of those awful algo-driven apps notice that I never watch short videos and in fact I often force quit the app the second they feed me trash I don't want to see.
And they keep doing it.