Trolls and spammers are not the problem. They can be dealt with by brute-force moderation. The real tragedy: the triumph of mediocrity. People with time on their hands drown out more valuable contributors. We've all designed discussion systems with the most avid commenters in mind. We've given them stars and moderating powers and allowed them to develop cliques and a sense of ownership that shades into entitlement. They are not the only readers. They are not even the smartest of our readers.

