Perhaps a few tweaks can be made to the platform to help ensure HN's "core values" (that sounds silly) are passed on to new users. For the most part there's always been a good herd mentality to negate the one off low quality posts and a bit of public shaming "We don't talk like that around here...". Maybe a "Posting Guidelines" page and more weight added to the down-vote button to those that are privileged to have it could help.