Thanks for the feedback! Actually, the first version of our bulletin boards offered several subcategories, but the software we were using and our web server didn't like each other one bit.
As the boards grow a bit deeper and more active, I agree with you -- it would be nice to allow people to zoom right in, through subcategories, on exactly the type of info they're seeking.
At the same time, I'd like to allow people the opportunity to browse through all conversations that have been active in the past day, or week, or whatever, no matter what the topic.
Alas, this will take some custom-coding to accomplish! In the meantime, try out the search engine that's part of the new bulletin board software: It's quick and should get you where you want to go quickly.
The Old House Web firstname.lastname@example.org