Still use last.fm. Most "You might like this" algorithms go straight for the low-hanging fruit, and often fail to take any kind of nuance into account. I can't tell you how many of the streaming services will see my Black Sabbath play history and immediately recommend, "If you like Black Sabbath, you should love...Slipknot!" But I've never had a real person make that mistake, because a real person who looks at my las…
I had always assumed that recommendation algorithms didn't work on genres, but instead did a lookup based on something like: "You like X" "Person Y also likes X" "Person Y also likes Z" "I should recommended Z to you" (proportional to the number of people there are who liked X and Z, compared to other options) If this is the case (and perhaps I'm wrong), it's nothing to do with the algorithm not understanding the sub…
But no, that is NOT the way these other services recommend things.
Spotify, for example, recommends music that it thinks is related, but not necessarily liked by both groups of people.
For example, a person who likes Black Sabbath, and really technical instrumental metal, probably doesn't like the comparatively simpler slipknot. While some people who like slipknot may like black sabbath, but even less will be aware of really technically advanced instrumental metal.
music-map.com will take that into account. When you say "my three favorite bands are", you're not going to see slipknot show up in the result list, because people who mentioned those technical bands tended not to like slipknot.
But if you go to spotify and listen to sabbath, you'll see slipknot recommendations, because there is overlap, right?
I just went over to music-map right now, and sure enough, black sabbath and slipknot don't overlap, even when you do searches of the bands individually, let alone if you enter multiple bands.