In my first salvaged post, I wrote about #movie recommendation sites!
I discovered MovieLens years ago when developing my collaboratively edited social news site way back when (a story for another time) - it is an #opendata recommendation platform that is also a research project by the University of #Minnesota.
It also predates the current #AI revolution, if that matters to you.
https://www.quippd.com/social/comments/2017/03/02/movielens-personalized-movie-recommendations.html