Which music retail innovation first utilized collaborative filtering algorithms to recommend music to customers based on their previous purchases and listening habits?

The music industry has undergone massive transformations in how products are sold and consumed. From vinyl records to digital streaming, music retail has embraced technological innovations that changed consumer behaviors forever. This trivia question focuses on a pivotal moment in music retail innovation that altered how consumers discover and purchase music. Test your knowledge about the evolution of music retail technology!

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Apple's iTunes Genius feature (2008)
Pandora's Music Genome Project (2000)
Amazon's recommendation engine for CDs (1998)
Spotify's Discover Weekly playlists (2015)