The Internet increasingly serves as a platform for the delivery of public health interventions. The efficacy of Internet interventions has been demonstrated across a wide range of conditions. Much more work remains, however, to enhance the potential for broad population dissemination of Internet interventions. In this article, we examine the effectiveness of Internet interventions, with particular attention to their dissemination potential. We discuss several considerations (characterizing reach rates, minimizing attrition, promoting Web site utilization, use of tailored messaging and social networking) that may improve the implementation of Internet interventions and their associated outcomes. We review factors that may influence the adoption of Internet interventions in a range of potential dissemination settings. Finally, we present several recommendations for future research that highlight the potential importance of better understanding intervention reach, developing consensus regarding Web site usage metrics, and more broadly integrating Web 2.0 functionality.