It would be nice if you could see which category you are in when you have entered one, because right now you actually can't (i.e. elsewhere than in the url).
Sometimes I first enter for example Opera for *nix, then I go to a discussion, and then I go back. Now I want to see which category I am in. To clarify, I am talking about these sites; forums.opera.com/categories/<category>, for example forums.opera.com/categories/en-opera-for-windows.
I queried that some time ago here -