Sermo describes itself as a “virtual doctors’ lounge” where physicians can express their opinions and interact with other doctors. One of the newer features on the physician-only social network is the ability to crowdsource solutions for difficult cases. We spoke to Erin Fitzgerald, senior vice president of marketing at Sermo, about the social networking platform, how it’s used to solve hard-to-crack cases, and the business model underlying the free service for physicians.