they probably log a 'shadow view' but recommendations seem to be directly based on your watch history since your recommendations are lost when you completely clear it.

That is a bit odd because I have had watch history off for years, but I still get recommendations that make sense.

Do you subscribe to any channels? Have you liked any videos?

Ah, yes, I have liked some videos throughout the years.

The recommendations will mostly be derived from the videos you have saved in playlists. And the front page will always shows Youtube Mixes about the last song you were listening to, at the time of turning off the watch history.

Do a significant amt of YouTube users use playlists? I’ve always assumed no. Unless perhaps they are doing it for music since you’re talking about YouTube Mix. And songs.