I hope we don't come across that strict
They really are crossed categories, with the four main categories defining level of detail (battlemap, city, regional, world).
Then we have some forums for genre (sci-fi) and purpose (VTT, board games) to make these more visible.
The CL's have been discussing adding prefix categories or tag picks to threads to help with the organization, but this could get cumbersome. The best thing is to drop it where it fits best, and add lots of good tags to it can be found through searching!
-Rob A>