Adding relation information between tracks, albums and artists to beets?

I've been playing with the thought about adding `relation` information to beets. With `relation` I mean a `weighted` connection between 2 tracks, albums or artists. These relations could be initialized with e.g. similar track or similar artist information gathered from [Last.fm](http://www.lastfm.de/api/show/track.getSimilar) or based on other data (e.g. [Acoustic Attributes](http://developer.echonest.com/acoustic-attributes.html) from the Echo Nest come to mind). They could later be refined manually by the user or automatically e.g. by tracking the users listening habits (plays and skips).

This could provide for smarter playlist creations or plugins that hook into media players to fill the queue with suggested tracks. I do something like that with my [Advanced Shuffle Client for MPD](https://github.com/pscn/ads).

There are a lot of open questions regarding this feature, but before getting into details, I wanted to get a vibe if it is even desired to have something like this in beets.

Any opinions about this?