Submission + - Social influence and the wisdom of crowd effect (pnas.org)
Social influence.
While previous studies show how groups of people can come up with remarkably accurate results, it seems " that even mild social influence can undermine the wisdom of crowd effect in simple estimation tasks." Social influence "diminishes the diversity of the crowd without improvements of its collective error".
In short, crowd intelligence only works in cases where the opinion of others is hidden. So, slashdot moderation good, American pundit-democracy bad?