(Be sure to check out the List of Medical Wikis)
The aim of Radiopaedia.org is to develop an online text where information is up to date and relevant to the needs of radiology staff, both registrars and consultants. In addition, the wiki format will allow discussion of topics and resolution of areas of confusion. There are many worthwhile online resources already, however most are not collaborative and therefore lack the ability to respond to users needs.
This appears to be the editorial policy:
Anyone can create an article. Anyone can edit an existing one. Contributions remain logged to your name, and can be included in your CV, along with a link to your User Page.
Due to the immediacy of editing, new information can be introduced immediately when it becomes available. Errors can be corrected immediately, with no need to wait for the next edition.
I have to admit that I enjoyed the disclaimer:
None of the information here is to be used for self diagnosis or treatment. If you suffer from a medical condition, or think you do, please go see a doctor. We do not accept responsibility for you failing your exams either, not that you will of course.