There is considerable evidence, across different clinical contexts, that treatment decisions are characterized by poor communication, significant knowledge gaps, and a lack of attention to patients' preferences for different health states. Over the past two decades, patient decision aids have been shown to be an effective means to improve the quality of decisions. More recently, the Internet has increased expectations about the impact of information and decision aids on the involvement of patients in decisions. However, there are several challenges to effective dissemination and implementation of decision support interventions, through the Internet or other media. The authors recommend specific policy and research initiatives to facilitate the local and system-level changes necessary to support patients more effectively in making treatment choices. More attention to measurement and policy-level interventions will be required to increase the use of proven tools and to achieve significant improvements in the quality of treatment decisions.