In April 2009, CDC launched Act Against AIDS (AAA), a five-year, $45 million initiative intended to combat complacency and raise awareness of HIV and support the reduction of HIV incidence in the United States. AAA is an umbrella program that comprises social marketing campaigns and multiple community partnerships. AAA and its sub-campaigns use a comprehensive marketing approach that includes traditional paid media -- print and out-of-home advertising -- online resources, social media and earned media to reach intended audiences. Each campaign leverages digital and social media, as appropriate, to extend the reach of campaign messaging, engage audiences in discussions related to HIV, and drive audiences to a wide range of prevention resources. In March 2010, CDC launched @talkHIV on Twitter in support of i know, a social media pilot initiative intended to increase dialogue related to HIV/AIDS among African Americans, ages 18-24. Similarly, with the launch of the most recent AAA sub-campaign -- Let’s Stop HIV Together– CDC launched a Facebook page and began using YouTube extensively. These digital activities have the potential to reach a wide audience. Facebook has more than one billion active users who generate an average of 3.2 billion Likes and Comments per day. Twitter has half over 500 million users, with 150,000new users signing up each day. YouTube is the world’s second largest search engine, with 1 in 5 people watching health videos weekly. This panel will offer insights into opportunities and challenges when using these three digital media outlets to disseminate public health messages.