WordPress categories are based on xfml, the xml standard for faceted classification, also known as multidimensional classification.
WP user interface doesn't fully implement the powerful possibilities offered by faceted classification.
Look at http://www.facetmap.com/browse/?v=selection2yahoo.xsl&s=01000000011f&n=2 to understand potentialities.
Has someone implemented a similar interface?
Thank you very much