For some silly reason we don't track downloadable games yet. We track them on consoles, but why not PC/Mac? Probably because some would think that opens up the possibility for any old game to be added.
We have 35 IBM PC and 1 Mac game listed as downloadable in the database and have tracked downloadable games since we added the media format ages ago. It isn't more prevalent because users aren't submitting games for those systems is all. Remember the console services are unique to each system and while the PC/Mac have dozens of networks, retailers and websites selling games we couldn't possibly track each one so they remain in their main system section.
Apple Mac region free has been added. Remember to only use it if your sure only one localized version exists of a title. If your able to download it in several languages based on your location, they have to be listed by continent as others are.