My collection is so large and sparse, that separating them by a single category is not enough. I want to separate them by genre according to each platform and not have all platforms displayed when finding a game by genre! I have too many PC games in my collection to share amongst my collection of emulators when I want to split them up by genre or theme or whatever. If you guys could give us the option to have sub-categories, it would make a lot of difference for people like me with a boat load of games stored on their computer.