Brightonart is currently involved in a series of new developments on the Drupal module Taxonomy NCO - AKA 'Matchy matchy', this module derives inferred semantic relationships from large folksonomies that tend otherwise to fragment and become unmanageable.
The module was originally developed in Drupal 5 as part of the School of Everything project. I am reposting this original blog post to preserve some technical background:
Russell Blakeborough
School of Everything
May 2009
Summary