I never use any websites forum like I think it was programmed to be used, so let's start with that and acknowledge this suggestion may not be necessary at all for most people. But, for me, I'd like to have the Mark All Read ability at the top of the page, and maybe at the bottom of the page as well. It would also be nice if it was a button instead of a dropdown. In fact, I'd like to have a button on the main forum page to mark ALL forums as read, if that's even an option.