I'm someone else who refrains from commenting in order to protect my average karma.
The thing is, that it isn't as irrational as you are making it out to be. Posts from users with higher average karma are sorted higher. Presumably you are posting because you want your post to be read. Either you want it to influence people or you want your question answered, or whatever. If you didn't want it to be read, you wouldn't have posted it.
I'm pretty sure this has a 'rich get richer' effect. On a page full of a lot of comments, most people will only read the first few. Being at the top leads to more up-votes, leading to more posts at the top, and so on recursively.
I am totally guilty of gaming this system. I normally only post in threads where I think that I'll get up-votes, and I only post things that I think are worth posting. The latter effect is good. There are too many people on HN and it's a good thing to encourage us to maintain a high signal to noise ratio. But the former, the fear of posting in unpopular threads, or on comments near the bottom of the page, is awful.
I suspect the average karma preference has a negative effect on quality, as you've pointed out. There is incentive for the best commenters to only comment occasionally, when they'll get a lot of karma for it.
Digg kept piling on stuff like that, making some users more valuable than others according to the algorithms, and I think it hurt rather than helped. I'm not sure it hurts on HN, but it doesn't seem to solve the core problem, either.
I think it does come down to a social problem being tackled by technical solutions. It may be that the only way to make this problem go away is to empower moderators (of which HN has more than a few) to simply remove the most negative stuff before it has a chance to alter the tenor of a thread. Hostility breeds more hostility and it spirals ever upward, until the conversants are more frustrated than talkative.
Wow, I had no idea average karma sorted people higher/lower.
But you actively try to protect your karma? After my karma hit 1000 I basically stopped caring anymore. What incentive do you have to protect your karma (serious question, I'm not sure I understand why it matters)?
I didn't know this, either. This idea will only work if karma measures what we want it to measure. If karma isn't associated with quality but with site-gaming, or snarky commenting, or other bad stuff, this system creates a positive feedback loop for sending the site in the wrong direction. Yikes!
I thought the sorting of comments was based on the votes for that comment in that thread, not based on the average karma of the poster. Is that not the case?
If 5 of us post in a thread at the same time, and no one upvotes any of the comments for an hour, then the ranking of the posts is going to have some kind of dependency on our karma metrics, rather than a "first come first serve" ordering.
The thing is, that it isn't as irrational as you are making it out to be. Posts from users with higher average karma are sorted higher. Presumably you are posting because you want your post to be read. Either you want it to influence people or you want your question answered, or whatever. If you didn't want it to be read, you wouldn't have posted it.
I'm pretty sure this has a 'rich get richer' effect. On a page full of a lot of comments, most people will only read the first few. Being at the top leads to more up-votes, leading to more posts at the top, and so on recursively.
I am totally guilty of gaming this system. I normally only post in threads where I think that I'll get up-votes, and I only post things that I think are worth posting. The latter effect is good. There are too many people on HN and it's a good thing to encourage us to maintain a high signal to noise ratio. But the former, the fear of posting in unpopular threads, or on comments near the bottom of the page, is awful.