The rapid emergence and exploding usage of online social networking forums, which are frequented by millions, present clinicians with new ethical and professional challenges. Particularly among a younger generation of physicians and patients, the use of online social networking forums has become widespread. In this article, we discuss ethical challenges facing the patient-doctor relationship as a result of the growing use of online social networking forums. We draw upon one heavily used and highly trafficked forum, Facebook, to illustrate the elements of these online environments and the ethical challenges peculiar to their novel form of exchange. Finally, we present guidelines for clinicians to negotiate responsibly and professionally their possible uses of these social forums.