This document discusses the intersection of social media, public policy, and sustainability. It outlines four key properties of information flow in social media: reciprocity, durability, traceability, and scalability. It argues that putting the public back at the center of public policy requires enabling citizen participation in decision making through social media. However, the properties of how information spreads on social media must be considered. Government, civil society, and business often have differing values and goals, creating distrust that social media could help reduce through bidirectional interactions, durable content, and transparency. Elements like audience, issues, platforms, and lifecycles must be considered in social media campaigns related to public policy and sustainability.