This document discusses the potential for using virtual worlds for social good. It provides examples of how organizations like the American Cancer Society, Center for Disease Control, and schizophrenia research groups have used virtual worlds like Second Life for fundraising, health education and information, and to simulate the experience of living with schizophrenia to increase awareness and empathy. Challenges of virtual worlds mentioned include unintuitive interfaces, small relative audiences, and lack of interoperability between platforms.