At last a replacement for TuneGlue. EMI killed that probably by accident, about a year ago. Try this instead as a tool for exploring n-dimensional music artist space. http://musicroamer.com/ It's the same kind of idea. Put in one artist, it will build a rubber band spider diagram of related artists. Double click on one to expand it.

This is mainly based on last.fm and discogs algorithms, data and APIs. The reason for mentioning it here is that it should be possible to build things like this on top of Google Play Music and Youtube Music Key.