I am going to share a piece of anedoct. There once was a very nice German-based application called Foundd. The app was soecialised in movie recommendation and

I am going to share a piece of anedoct. There once was a very nice German-based application called Foundd. The app was soecialised in movie recommendation and it was awesome: great interface, good filtering, good recommendations. Then, they introduced TV shows recommendations. As soon as I started rating TV shows, the quality of my movie recommendations plummeted. I guess my general dislike for TV shows wasn't helping the algorithm. It seems really hard to build useful cross-domain recommendations.