Hi there,
Please remember that wikipedia's "category-tree" is far from a
hierarchical system like UDC and dmoz. Some use it for classification,
some as keywords like tags in del.icio.us or flickr. Be sure not to
implement category-features not with something like "This use of
categories is wrong and this use is right" in mind.
In my opinion (and with my study of library and information science)
you will *never* get a strong hierarchical system like UDC and dmoz
because everybody can change everything. Please keep this in mind.
Greetings,
Jakob
P.S:
http://www.wikipedia.org/wikistats/csv/ is not reachable :-(