dates to Web site visitors (e.g., Folic Acid Campaign), tailored e-mails to campaign members or volunteers through electronic mailing lists (e.g., National Truth Campaign), and personalized reminders to promote the desired health behavior (e.g., annual mammogram reminders by the National Alliance of Breast Cancer Organizations). Some campaigns have developed Web sites that are responsive to the unique needs of diverse audience segments, such as the National Youth Anti-Drug Media Campaign, which offers content-based Web sites for parents (http://www.theantidrug.com), teens and “tweens” (http://www.freevibe.com), teachers (http://www.teachersguide.org), student journalists (http://www.StraightScoop.org), and other audience segments.

Message executions involve many specific decisions. Two important ones include the basis offered for the credibility of a promised reward and the image projected by a campaign. One important basis of credibility is the source or person(s) communicating the message. Different audience subgroups may find different sources of information to be persuasive. For example, scientific findings from an expert source may be the most important and credible evidence to one audience segment, while information on social norms from a peer may increase perceived self-efficacy and offer better support to another audience segment.

The source and support for messages may reflect the health issue or topic of communication as it is seen by a particular audience. Some issues may be naturally “medicalized” for a particular audience and thus there is a reliance on sources that offer immedi-