However, if you expose the gods of the algorithm to a new artist, suddenly all the auto-generated feeds will try to include that band regardless of fit. Weird how these "social graph" systems tend to form and perpetuate bubbles.

On top of that, there are some weird shenanigans with meta-data. Listening to "foreign" bands may very easily taint the weekly mix with songs in a language you don't even understand and probably don't care about. An anecdata of course, I just looked at my "daily mix x", which appears to be in my local language, but with styles all over the place. Another mix contains mostly correctly turn of the century romantic pop.

I suspect the algorithm biases heavily on metadata so that it could be easily fed "albums/artists that publisher x paid to promote".