A lot of people cite MetaTalk as a reason that MetaFilter works. If you talk to a regular from the site they'll tell you MetaTalk is key to the success of the site because it's a sort of release valve.
The solution to the "not hacker news" problem isn't to shout people down. You need to give them that release valve. The comments are a symptom of a problem, and it needs to be addressed through the site architecture.
I tried out and stopped using the JoS discussion boards (way before the days of reddit) primarily because this release valve didn't exist. My submission would occasionally get magicked away and there was no recourse, no way to ask why that had happened.
could be handled by directing people to a posting about hacker news, where they could comment to their hearts content (or, hopefully, read historical conclusions to their comment's topic, if one already exists)
