I'm not sure if we really need new categories as such, but I can imagine that a OP could be "tagged" to belong to a specific category like regex question, cgi quesion, DBI question, etc. New questions would go "unspecified" unless at least x people tag it to such a category.

This tagging could work similar to the approval process. There would be a "Tagging Nodelet" where you have a dropdown list (that lists the categories) and a button to submit your tag.

This would only require a single additional field in the database, that could then be Super Searched upon.

just 2 cents,