I just notice how messed up the search is very recently. One of the things that it does is that it uses search terms from previous searches in the results for a specific search, it's awful for people with diverse weird interests. My example I was searching for "primitive garden irrigation systems" after searching for some "city building games". Half of my results were "water canals in city skylines". It's both useles…
It's likely a success if you only measure click though rate, i.e. someone loses focus of what they were trying to do because they are presented something similar that is very salient and switches to that context. I've certainly noticed that more and more with features like "frequently opened sites" YouTube's recommendations, a highly targeted ad etc
How long someone watches a video is deeply tracked and even impacts creators revenue