Node association by user flags

I have a 'band' content type on my website, and users can indicate whether they are a fan of each band (much like Facebook's 'become a fan' system, before they changed it to 'like').

I wanted to recommend bands to users based on this data: for each band, I wanted a list of 'similar' bands to be displayed (so the recommendations are not user specific, so as to cater to anonymous users as well). Most recommendation modules I found couldn't do what I wanted. The Associated Nodes module is a perfect fit because of its plugin architecture: I whipped up an 'Associated Nodes Flag' plugin (it depends on the flag module, obviously), which associates nodes based on the amount of users that have flagged both of them (it doesn't work for global flags, of course). The exact algorithm is described here: http://got-djent.com/content/how-new-recommendation-system-works

The code isn't very clean, I hardcoded some things like the beta parameter which controls popularity bias, but nevertheless I wanted to share it in case someone else finds it useful.

It's too bad that this module isn't being maintained at the moment because it's proved very useful for me. Views support would make it excellent (I used the workaround mentioned in #603096: One method of views support). Thanks!