Discoverability...

I'd pay handsomely for an app that did discovery on tracks and not artists. Last.fm kind of but not really does it. It took me many years to get from Sirenia: Seven Sirens And A Silver Tear to the Midnight Sonata (I can't remember alas who did it -- was it reddit or a forum on a now defunct tracker? all the great trackers are dead) and from there I was able to branch out. But this shouldn't be so hard..? We already have several music matching apps, surely closeness is a solvable problem.