Within the US, consumers are assuming a much greater role in actively managing their own health, educating themselves regarding health problems, and facilitating interventions to improve health outcomes. The Internet is a convenient and cost-effective enabler for supporting patient-centered healthcare. It is a wellspring of knowledge; a virtual, global community center; and a simple and convenient infrastructure for enabling consumers to monitor their own health states. For the Internet to successfully fulfill its role in health and disease management, a number of significant challenges must be addressed. Foremost among these are unfamiliar and difficult clinical vocabulary, lack of quality control, unequal accessibility, and risks to personal privacy.