Keeping Web Discussions Open, Yet Civilized?

gsnedders asks: "With the rise of 'Web 2.0' and user created content, often in the form of comments, how do you keep the discussion open, yet civilized? I've found Slashdot's moderation to be very good — the good stuff gets moderated up, and the bad stuff down. On Digg, correct and valid information often gets dugg down, and offensive comments up, showing that having an open moderation system doesn't always work. However, moderation like on Slashdot, requires a large numbers of users to have enough moderators without giving everyone moderator access, therefore making it impossible to use on smaller sites. How can you keep the discussion civilized, while keeping commenting open, and not requiring large numbers of users for the moderation to work?"