I've notice new WordPress Frameworks and Themes coming out designed to be Web Responsive (aka Mobile and Tablet Friendly). I've also been informed that you can have a "Web Responsive" Theme, but have it respond incorrectly if a "Non-Responsive" Plugin is enabled (CSS issue?).
How about a new category "Responsive" or "Web Responsive Design" in the Free Themes Directory's Tag Filter?
A new "Responsive" or "Web Responsive" Plugin Category?