Holy crap. This is going to trigger a five-alarm fire at Spotify Engineering. This has got to be among the largest proprietary datasets ever unintentionally publicized by a company.

Wasn't all data available to users though?

I mean... not really? Not much music is Spotify exclusive (at least from the 99.6% of what people listen to mentioned in the article), and from friends in the industry I can guarantee you all major content platforms (Netflix, Disney+, Prime Video, a large chunk of YouTube) have already been completely copied without a business agreement with the rightsholders by AI startups and big-name players.