As we use social tools on the web, design patterns are emerging. Social design must be organic, not static, emotional, not data-driven. A social experience builds on relationships, not transactions. In 2008, Yahoo!'s Christian Crumlish introduced the idea of social design patterns to BayCHI. In this 2010 program, he shares what he has learned, including principles of social design: Pave the cow paths. Talk like a person. Be open. Learn from games. And respect the ethical dimension.