The most important secret sauce is the recommender system. It takes into account transcripts, color historgrams of frames, actions and activities recognized in videos, frame cuts frequency, key personalities and entities recognized and what not. That's my humble guess.
Sadly that secret sauce has become fairly poor. Recommendation issues is the biggest problem with YouTube right now.
I can open YouTube on any given day and will be given recommendations for things I've never shown the slightest bit of interest in.
For example, right now I've got:
- A clip for the big bang theory - Never watched anything on that show on youtube
- "Why does italy have 6000 ghost towns (Hidden Italy)" - Absolutely no idea why it thinks that would interest me, never been to Italy or watched any kind of travel based videos.
- "I hitchhiked Onto A Private Jet To Werever It's Going" - Again, I couldn't give a damn
- "The Legendary World of Spyro Games - Caddicarus" - I have no idea what that is, or why it thinks it interests me.
- "Singapore welcomes 2023 with New Year fireworks at Marina Bay" - Ok, and? Never been there, never watched any content about the place.
- "I called every U.S. Representative in the country. Here were the responses I got." - I'm not American, and give absolutely zero f's about US politics.
- "I've Been Living In A Ghost Town for Almost 3 YEARS!" - Good for you, I don't care.
- "Dark Secrets of the World’s Most Isolated Island" - Nope.
It has improved slightly from the looks of things. Usually I get videos about minecraft, or some twat gorping with their mouth wide open trying to make a mundane and uninteresting topic seem like something I should be interested in whilst remembering to smash the like button and click the bell.
I think this is a focused attempt to diversify the videos you watch and to avoid getting into a bubble. Journalists have dug into it and discovered that youtube's previous algorithms really seemed to automatically steer people towards the alt-right bubble. Before that, there was a bizarre trend of what looked like mass- or AI-produced kids' shows, but a lot of them had weird grooming shit in them like getting injections and getting pregnant.
My experience is different. My recommendations are all math and cs related. It is based in your watch history and you can remove things from your history and recommendations will change. If you haven’t watched many videos in your account then just find the type of videos you are interested in and prone the recommendations.
It's only partially based on history these days. The YouTube subreddit is ram packed with posts about the issue, it looks like 50% of your recommendations are relevent to you, the other half is randomly generated with seemingly nothing in place to at least try and match them up to your known interests.
It started approx 2 years ago and has gradually gotten worse to the point where some users see no recommendations relevent to them at all.
