I haven't seen many (any?) online systems that seem particularly well-suited to arguments.<p>Nevertheless I like it when sites try to call out clear statements of position, supporting and opposing arguments, citations for evidence for claims, and rebuttals, while trying to reduce logical fallacies such as ad hominem arguments, guilt by association, etc..<p>It also seems hard to have a productive discussion of controversial ideas without some degree of third-party oversight and moderation, but moderation usually favors the biases of the moderators and usually generates animosity among those whose comments are suppressed.