What you're describing is is similar how Allmusic categorises artists (categorised? I haven't used it a lot in the last few years, so I don't know how much it's

What you're describing is is similar how Allmusic categorises artists (categorised? I haven't used it a lot in the last few years, so I don't know how much it's changed). I used to find most of my new music via it. It was in no way algorithmic - it didn't make suggestions, it was just a case of manually following links (given that part of the pleasure comes from searching and discovering independently, no bad thing). It had genres, mood, influences, influencees, etc at the artist level at least. It would seem that Rovi's API could be better leveraged to provide good suggestions than it currently is, if all that metadata is still being attached (though there are things like Spotify's Discover Weekly that I've found to be surprisingly good which I assume use it). [It would have been even better if that had been expanded to album/song level. As the sibling comment suggests, categorising by subject matter would be very useful for a not-insignificant number of people as well.]