I know it's frowned upon to discuss downvotes, but I think it's relevant to the conversation. Godwin-evoking private forum moderators exercising their right to

I know it's frowned upon to discuss downvotes, but I think it's relevant to the conversation. Godwin-evoking private forum moderators exercising their right to police their turf aside, I always find self-moderating upvote/karma systems on forums interesting. Ostensibly the point is to allow users to control the tone of the site, and promote interesting, relevant content. In practice it is used to bury unpopular opinions and register distain. Some comments are justifiably downvoted for being of spectacularly low quality, whilst many others are hit for not reflecting prevailing opinion - essentially we (internet commentators in general, not specifically HN, although it's hardly exempt) actively squash Free Speech on a daily basis.