Comprehensive health campaigns are often charged with reaching a variety of audiences in order to increase awareness and understanding of an issue or to change attitudes, beliefs, and behaviors. These campaigns present messages via multiple electronic media platforms and other communication channels. Mass media advertising is still the most visible element of most public communication campaigns, including broadcast media (e.g., TV, radio) as well as print (e.g., newspapers, magazines) and out-of-home advertisements (e.g., billboards, transit ads, posters). These efforts are now being complemented by various digital media possibilities, including online advertising on the Internet and mobile platform messaging, as well as campaign-owned Web sites and campaign presence on popular social media sites (e.g., Facebook, Twitter, YouTube). Health campaign planners also promote their messages through public ...