Forum OpenACS Development: Response to Categories in OpenACS 4

I would second Don's notion. For the user interface I'd suggest that you have a link which allows you to create a tree view of you categories so you can pick one. Look at dmoz.org and something like this popping up when you want to add an item to a category. For code and demo how this works with ACES check it out from CVS (at sussdorff-roy.com).