The other day I suggested perhaps adding blocking to HN, mostly as a way of starting a discussion. And it led to some interesting ideas that I think are worth considering.
A lot of the personal attacks come from accounts created to post one message. The user has never commented before, or submitted a link to the site.
1. Add a waiting period before new accounts can post. Like registering a gun.
2. Charge for creating an account. Maybe $5 or so. Not very much money, but perhaps enough to make someone think again. If they want to be anonymous, use Bitcoin. That's what it's for.
3. Automatically downvote posts from accounts created within the last hour. Make it clear to readers that this comment was made by a new account.
What made me think of this idea was yet another one-off flame from a user named redmarx who created the account 13 hours ago, the exact same time his post was created. Now what do you think is going on there? A courageous whistle-blower, or a coward who doesn't want to own his or her own words? :-)