The Centers for Disease Control and Prevention in Atlanta has developed more than 80 electronic greetings to spread health information. More than 30,000 "Health-e-Cards" have been sent since the agency started posting them on its Web site in February 2007. The cards take research-based health information that the CDC has used in more traditional ways and put it into links inside cards for people to send to friends, family and co-workers. About one-third of the E-cards' recipients have clicked through the card into the agency's Web site for more information, CDC officials said.