WikiDoc was created to freely share medical knowledge and to foster collaboration among healthcare providers. Launched by Dr. C. Michael Gibson of Harvard Medical School in late 2005, WikiDoc is the first and largest wiki dedicated to medicine on the Internet. WikiDoc is kept up to date by over 5,000 collaborators around the world. The content has now been updated nearly half a million times. There is no pharmaceutical or device industry support for the site. WikiDoc is intended to be a free shared resource for housestaff (in preparation for morning report), medical students (in preparation for morning rounds) and fellows (in preparation for conferences). Nurses and attending physicians may find WikiDoc valuable in improving and maintaining their fund of general medical knowledge. Registration not required.