I believe Spotify's discovery algorithms have factored in other user's playlists...

Wingman4l7 on Dec 7, 2021 | parent | context | favorite | on: A few things I’ve come to believe in my years in m...

I believe Spotify's discovery algorithms have factored in other user's playlists when trying to find songs associated to other songs -- that's why (in my experience, anyway) it has been better than the usual recommendation engines.