The document discusses how public health organizations can tap into viral memes and social media to change health behaviors. It provides an example of how the CDC used the social media platform MeetUp.com to encourage vaccination. The CDC campaign reached over 10,000 people and led to an increase in vaccination rates and positive attitudes. The campaign proved that using popular social media platforms can successfully encourage behavior change by allowing information to be shared and people to meet up for vaccination. However, public health communicators still face challenges in using digital and social media to both effect and measure long-term behavior change.