Have you used Experts-exchange.com lately? They seem to have figured this one out. The question data element itself should have a 1:many relationship with categories, similar to the cross post method you mentioned. The cutting edge right now is to use the question title to display context sensitive categories to choose from, and multiple categories can be chosen effortlessly.I can see this being the next new thing to hit Photo.net. I used to frequent the forums a lot and I know this would not only help to make posting easier, but also aide in getting visibility from a much wider audience of qualified members who can answer the questions.
-- Steve Tout, October 1, 2007