Design-Based Research (DBR) allows learning scientists to investigate new processes, contexts, and technologies for learning. Social Networking Sites (SNSs) offer researchers rich new opportunities to create educational interventions that are deeply connected to learners’ lives and relationships. We discuss legal and ethical challenges, and possible solutions to them, that face educational researchers as they begin to do DBR on SNSs. Addressing these issues will be crucial to design researchers wishing to use SNSs as sites for learning, and also offers an opportunity for the CSCL community to shape SNS research far beyond our field.