Which pioneering recommendation system feature did Netflix abandon after awarding a $1 million prize to improve it?

The film and television industry has been transformed by sophisticated recommendation algorithms that keep viewers engaged for hours. Major streaming platforms invest millions in perfecting these systems to increase watch time and reduce churn. How well do you understand the technology behind what keeps audiences binging their favorite shows and discovering new content?

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

The Netflix Prize-winning collaborative filtering algorithm
The 'Because You Watched' suggestion rows
The five-star rating system (replaced with thumbs up/down)
The personalized thumbnail generation system