This document outlines 5 principles and 5 practices for designing social interfaces, as well as 5 anti-patterns to avoid. The 5 principles are paving cowpaths, talking like a person, being open and playing well with others, learning from games, and respecting ethical dimensions. The 5 practices discussed are giving people identity and a social object, enabling activities and bridging real life and online connections. The 5 anti-patterns warned against are cargo cult design, breaking email conventions, weak password security, building a fake "Potemkin village" community, and an unbalanced ecosystem. The document provides examples and guidance for applying each principle and practice, and avoiding the anti-patterns.