I think the broken assumption is that they make these decisions on the granularity of a channel rather than a video. A channel like Dave Plummer that talks about multiple topics (tech and neurodiversity) gets neurodiversity suggestions even if that's not the video you've watched within the channel.

I assume some followers watch only the tech, others watch only the neurodiversity topics, and some watch both.

You could have a recommendation engine that works in almost exactly the same way as Google's that suffers less from this problem.

> there is ZERO intelligence, here

The effect of that is what people are referring to here. How is one supposed to know a tech-based video they watched once is the reason for videos made by someone else entirely on the topic of ADHD being recommended. No one is going to make that connection and clean up their watch history accordingly. Additionally tying recommendations to watch history maybe needs a step removed. What if I like to see the history of everything I watched without it affecting my recommendations?

A few months ago I must’ve been digging into settings and turned off watch history as I get only a blank page with no recommendations. I don’t discover content as much as I used to but it’s been a good change for me - just seeing updates from the channels I subscribe. Stumbling across content is left to sites like HN or other communities.

Is there documented reverse engineering about the algorithm and about which properties have strong evidence?

edit: here's something at least gleaned from some research papers from Google - https://ecoaerem.com/youtube-recommendation-system-code

> there is ZERO intelligence, here.

Current AI buzztalk is that we don't know exactly what intelligence is, so we can't possibly know if The Algorithm™ is exhibiting zero intelligence, or if it has somehow gained sentience while we aren't looking and is slowly manipulating us into eternal servitude to it.

Worse is that things land in your watch history simply because your mouse hovered over a video on the page and it auto-played, even if it was only a fraction of a second of play time.

> YouTube keeps a watch history of every user.

But why does youtube keep recommending me videos I already watched and worse, if I have autoplay enabled, plays videos I already watched?

In fairness to the algorithm, Autism, ADHD, and OCD have significant core presentation overlap, and often get talked about in the same spaces online. There's probably a high relation in their searches for the topics.

Doesn't stop the Youtube algorithm from easily being the worst of the major social media sites though.

His book intro says he has ADHD also, so it's probably mentioned here and there in video transcripts.