I just tested it out, and the way Ikonboard's categories work is the same as how Gossamer Forum's categories work (and most other forums). You're also limited to 1 level categories, ie. you can't make a test3 category, which is a subcategory of test2, which is a subcategory of test1:

I don't think that I've seen any forum which supports categories like how I posted above (probably because there isn't much of a demand for it).


Adrian