Which algorithmic approach revolutionized Spotify's recommendation system in 2015, significantly improving personalized playlist generation?

Music streaming platforms use sophisticated recommendation algorithms to personalize your listening experience. Behind those 'Discover Weekly' playlists and 'You might also like' suggestions lies complex machine learning technology that analyzes your listening habits, preferences, and even the acoustic qualities of the songs you enjoy. Test your knowledge about how these music recommendation systems work to deliver personalized music experiences!

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

Neural Collaborative Filtering (NCF)
Word2Vec-inspired audio embeddings
Bayesian Personalized Ranking (BPR)
Multi-Armed Bandit exploration models