Categorising content on the web
This article entitled Ontology is Overrated: Categories, Links, and Tags is interesting for any programmer who's had a client say they want a taggable/searchable/categorisable system of some kind. They're all the rage at the moment, apparently. The interesting ideas reall start in the mind reading section.
"One of the biggest problems with categorizing things in advance is that it forces the categorizers to take on two jobs that have historically been quite hard: mind reading, and fortune telling."
Ontology is Overrated: Categories, Links, and Tags