My pie in the sky idea (well, maybe not that unrealistic) is a music discovery service based on the emotions behind different musical progressions and the progressions themselves.
Ok, that sounds nice. But what does it mean exactly?
There are times when we listen a chord progression or harmony in a song or piece that changes something inside of us. You can feel it and analyze it while its happening, but you cannot invoke that same feeling without playing the song again and listening to it. Sometimes even, if you are not paying attention to the music, that fragment passes by and you miss your chance for the dopamine hit in our brain. Im not talking only about the goosebumps you get when you listen or play to something incredible, Im also referring to moments in songs that make you go "wow, that change was pretty clever".
Personally, songs that can emit that sort feeling end up being my favorite ones.
I use Spotify as my music streaming service but also used Google Music for a few years. With both, I sometimes get the feeling that the "Genius Playlist" algorithms could be way better. Often you end up in the same pockets of songs, albums and artists and I sometimes get the feeling that I've ran out of new music – that's ridiculous.
I believe that current music streaming services use connection networks ( If X users have this song on the same playlist as the seed song for the "Genius Playlist", then add it), and it feels pretty impersonal.
My proposal is simple: device an algorithm to study the progressions in the songs each individual user listens to the most, and by using some FFT magic, create new playlists that could trigger the same emotions and curiosity in the listeners brain.