Discussions of “Health 2.0,” first coined in 2005, were guided by three main tenets: (a) health was to become more participatory, as an evolution in the Web encouraged more direct consumer engagement in their own healthcare; (b) data was to become the new “Intel Inside” for systems supporting the “vital decisions” in health; and (c) a sense of “collective intelligence” from the network would supplement traditional sources of knowledge in health decision-making. Interests in understanding the implications of a new paradigm for patient engagement in health and healthcare were kindled by findings from surveys such as the National Cancer Institute’s Health Information National Trends Survey (HINTS), showing that patients were quick to look online for information to help them cope with disease. This paper considers how these three facets of Health 2.0–participation, data, and collective intelligence–can be harnessed to improve the health of the nation according to Healthy People 2020 goals. We begin with an examination of evidence from behavioral science to understand how Web 2.0 participative technologies may influence patient processes and outcomes, better or worse, in an era of changing communication technologies. The paper then focuses specifically on the clinical implications of “Health 2.0” and offers recommendations to ensure that changes in the communication environment do not detract from national (e.g., Health People 2020) health goals. Changes in the clinical environment, as catalyzed by the Health Information Technology for Economic and Clinical Health (HITECH) Act to take advantage of Health 2.0 principles in evidence-based ways, are also considered.