Clay Shirky on moderation strategies:
Social software is the experimental wing of political philsophy, a discipline that doesn't realize it has an experimental wing. We are literally encoding the principles of freedom of speech and freedom of expression in our tools. We need to have conversations about the explicit goals of what it is that we're supporting and what we are trying to do, because that conversation matters.
Anyone considering developing people-centric tools and services should read about these patterns.