I talked about this more in detail:

http://news.ycombinator.com/item?id=208748

To quote:

It is not ridiculous, since people aren't downmodding to express a difference of opinion about what the person said. They are downmodding to assert they do not want to hear any political opinion on Hacker News, because--as has been said--there are countless other venues for hackers to express and debate political opinion; Hacker News is not one of them.

Notice therefore we see something interesting regarding the HN system. In essence, this is exactly what pg had in mind. Karma is taken away for comments and not just submissions, so that users will adapt to the Hacker News atmosphere. As we have seen from this thread, politics (even "news" like the first ever black general election presidential candidate) is simply not something people are interested in seeing on HN, and if people keep discussing it, they will be downmodded into oblivion, effectively maintaining the current HN mindset (since, presumably, people with negative, or quickly decreasing karma, will not want to continue posting on HN).

The only thing that could break such a system is a vast shift in the mentality of the community (which is not a bad thing since it would still keep the community happy, although it's very unlikely to happen), or a massive influx of new people into the community (which is why pg wants to keep the number of new signups per day low).

Modified:

Upvote = "I'd like to see more comments like this" || "I agree with this".

Downvote = "I'd like to see fewer comments like this".

If enough people upvote purely for agreeing, it becomes possible to get karma for vapid posts that pander to the community.

I think it would be better to just factor in agreement as part of whether you'd like to see more. Maybe you agree with something, but the sentiment has been expressed so many times that it's getting tiresome.

Actually:

Upvote = "I'd like to see more comments like this" || "I agree with this".

Downvote = "I'd like to see fewer comments like this" || "I disagree with this".

the problem with downvotes is that the parent of this comment being downvoted is more likely to be because someone didn't know what || means rather than because someone wanted fewer comments suggesting minor, helpful improvements on the parent idea.

You are absolutely right, although it seems to me that to a growing number of users Downvote = "I disagree" or "Everyone is downvoting so I'll follow" or "You cannot disagree with this particular user so I'll downvote".

I think downvoting should not be. It is an unnecessary evil. A "dichotomy". Fighting for Peace using nuclear power. The best way to fight comments/posts that add no value is to Remain Silent. If you hit someone, there are very likely to hit you back, but if you ignore them they are more likely to take their rants and stories to Digg or somewhere else.

I disagree (although I upvoted your comment because it's a worthy contribution), if you're going to downvote a person at least share with us why you disagree and help us all glean some sort of understanding of your viewpoint.

No use adding flame infinitum.

What I mean is I do not need to downvote nor comment if I believe it is not worth it.

I would suggest limits on the number of karma points we can use each week or day (with no rollover) and eliminate the downvote feature.

In the case a comment or story is inappropriate, it can be flagged.