[erikbern]

We had to build some explicit filters for this at Spotify. For instance we blacklisted Christmas music from being part of the listening data – until them people would get a ton of Christmas music recommendations every January. But to your point, there's a long tail of other contextual things.

[lobster_johnson]

Weirdly, some genres seem to be entirely absent. I listen to a lot of jazz and classical, and with the exception of the occasional jazzy pop song, I never get recommendations for those genres.

Granted, Spotify doesn't have a huge amount of contemporary jazz (much of what I listen to are imported ECM tracks that Spotify doesn't have, though not all), but it does have a lot of classical.

I don't think it's ever recommended any Latino or folk music, either, come to think of it.

[erikbern]

classical music has notoriously bad metadata on spotify – it just doesn't fit into the data model of artist/album/track. i think that causes the system to filter out a lot of the listening data or fail to find patterns.

not sure what's up with jazz but i'm guessing it could be a similar problem