A number of years ago I had a post which listed some of the music which Paul Dunn and I used to play on the Sunday night radio show we hosted in Canberra. With the arrival of Spotify I revisited the post to create a playlist of most of this music, or at least those songs that are available on this music service.
Recently Spotify added a 'Radio Station' feature, which I am still trying to work out. It seems that it takes a playlist, and then chooses other songs that match the theme/style/artists on the playlist. I assume it has a number of algorithms that do this matching, and most of the suggestions seem fairly thematic. There of course may be some voodoo involved as well, as it keeps tossing up 'Golden Brown' by the Stranglers, which I don't believe was ever played on the show, but is one of my wife's favourite songs.
However there is the occasional song which doesn't seem to fit, unless I do a little bit of extra digging. It seems that it isn't just the style of music that is considered, but also the album/single artwork. So every now and then there will be a band who decides that putting a chess board on the cover of their album carries some gravitas. And that is how they slip into my headphones.