We use two tactics to pull this off. The first is our platform. We've built a fully customizable discussion platform that enables us to control everything from the timespan of a discussion to who carries the most weight once it's going. The second is that we put in old school editorial work to identify and bring the smartest and most relevant people to a particular discussion. We choose topics like Open Gov Data, research qualified people to invite, then create a prompt aimed at getting a cross section of those people to talk to each other.