crossref and sermo partner up...

DOIs will back the links from discussion to content...

CrossRef, the publisher linking service, announced that it has entered into a strategic partnership with Sermo, the largest online physician community. Through this new partnership, Sermo will make use of the DOI® (Digital Object Identifier) to link real-time physician discussions about current research to the source medical journal articles.

other more 'social' health sites are...

iMedix, which won best new startup at the TechCrunch Crunchies 2007

iMedix is a free website that helps you find and share health information. At iMedix, you are not alone, coping with fear and confusion regarding your medical condition. Whether you're looking for symptoms, diseases, treatments, or simply general health information, you will be searching together with many other people. Members of the iMedix community assist each other by sharing their experiences and ranking medical content in order to make health information personal, organized and accessible to any individual.

and the still to come google health