Recent estimates suggest that nearly three-quarters of American adults have looked online for health information. Typical search query results might include online discussion forums, information repositories vetted by doctors, personal and professional blogs, articles in academic journals, individuals' Web pages, and commercial or nonprofit Web sites. The sources of this information might range from renowned experts with impressive medical credentials, to pharmaceutical companies advocating the use of their product, to patients who have personally experienced medical conditions, courses of treatment, and medications firsthand. For people facing medical decisions, online information is also likely to be integrated with information coming from several off-line sources, including doctors, other health care professionals, and family and friends. Accurately assessing the credibility of the myriad sources of health information available ...