The CDC has a pilot HIV/AIDs prevention campaign that uses videos made by college students sent via cell phones to friends. The agency is exploring using the same type of cell phone videos for smoking cessation, according to Mullins.

The CDC is just getting started.

"We're getting our toes wet" with social media, Mullins said. The agency plans to expand its reach of social media and share what it learns with HHS and other federal agencies.

At a workgroup meeting last month of the American Health Information Community, federal officials and stakeholders explored the possible use of social media to promote personal health records. Jay Bernhardt, director of the CDC's National Center for Health Marketing, said any kind of federal push to promote the dissemination and uptake of PHRs will likely take the use of social media. Consumers respond best to messages from trusted peer sources rather than from authoritarian information from the top down, he said.

Janice Nall, director of the CDC's e-Health Marketing Division, said, "The positive uses for social media are staggering when you start to think of the health implications."