Policymic has this essay by Daniel Kamerling, advocating approval voting. The article specifically says the contest for the 2012 Republican presidential nomination would be improved if presidential primaries used approval voting.
Policymic calls itself “an online news platform to engage millennials in debates about real issues.” The term “millennials” generally means people born after 1982, who were graduating from high school at the dawn of the current century. Thanks to Rosa Barker for the link.