Sadly I'm not a developer - so I'm looking for one! But here is my idea:
It's a Spotify app that learns what people listen to, and creates a database of patterns. Those patterns are used to automatic(g)ally suggest the next song.
A first iteration would be a "simple" Spotify App, but the "pattern-creation-function" could be used on everything. I'll give more detail if somone is interested in hearing them.