system
A chat on subreddit /r/wallstreetbets
human
I've got thisnpet theory that Netflix has had such a large audience for so long that they have got an immense amount of data on people's likes and dislikes. Meaning they can get a better hitrate when it comes to picking shows. 
  
 Which they'll need when it comes to getting a return on their investment. 
  
 Not that I'm actually long on Netflix.

gpt
TV shows aren't as personalizable as adverts, consumer goods, etc. Millions of people watch the same few TV shows; the content is either good or it's not. It varies way less based on taste compared to pretty much every other thing that is sold. I'm sure they have plenty of data but I seriously doubt it's particularly valuable data.