The AHRQ WebM&M Web site represents an unprecedented effort to publish illustrative cases of confidentially-reported medical errors on the Internet, accompanied by straightforward evidence-based expert commentaries. Modeled on hospital morbidity and mortality conferences, five cases are posted each month to illustrate diverse patient safety issues. The Web site has become a popular source for medical error case information and has garnered positive feedback. As of March 11, 2005, 296 cases had been submitted, and 90 had been posted on the site. Twenty-four percent of the cases appearing on AHRQ WebM&M resulted in death or permanent disability. The site had 9,767 registered users and 663 unique visitors daily; the average visitor stayed for 12 minutes. Responses to a May 2004 user survey indicated that visitors were divided almost equally between providers (half nurses and half physicians) and nonproviders with an interest in safety. Seventy-five percent of users rated the educational value of the site as “excellent”; virtually all the others rated it as “good.” Similar response rates were tallied for questions regarding practical value, patient safety content, cases, commentaries, and continuing education. These results demonstrate a willingness on the part of providers to report medical errors under favorable circumstances, as well as a strong demand among health care professionals for Internet-based information pertaining to patient safety. Thus, AHRQ WebM&M represents one of the modern era's most successful experiments in patient safety reporting and education.