I like to ask metaquestions that emphasize the positive from time to time, usually just after someone has complained about how HN is going to the dogs. Here are some examples, which I also have linked in my user profile:
Ask HN: How Can I Make Better Submissions to HN?
Ask HN: What Kinds of Comments Should Be Upvoted?
Ask HN: How Can We Help Make HN a Better Online Community?
Ask HN: What do you like about the Hacker News community?
I'm seriously interested in anyone's response about what the difference is between high-quality posts and comments and lower-quality posts and comments. If we can reach consensus on that, we'll all know how to use whatever voting and flagging powers we each have.
I am currently working on a "specialised" social bookmarking site and have gone with only up-votes (posts and comments)and a facility for flagging spam or the inappropriate. I am confident that this simple approach will share some of HN's benefits.