Consumers are eager for information about health. However, their use of such data has been limited to date. When consumers do consider data in making health care choices, they rely more on word-of-mouth reputation than on traditional quality measures, although this information has not necessarily been readily accessible. The Internet changes the exercise of quality measurement in several ways. First, quality information--including reputation--will be more readily available. Second, consumers will increasingly use it. Third, the Internet provides a low-cost, standard platform that will make it vastly easier for providers to collect quality information and pass it on to others. However, major barriers still stand in the way of public access to quality information on the Internet as well as of having that access actually improve patients' care.