Okay, so this post may annoy some HN loyalists but it's also a reality that all communities need to deal with eventually. Keep in mind there is a high-probability that someone has already implemented this IKP.
Let's turn this lemon into a shandy and figure out what to do about it.
That comment gets an upmod for being a fertile suggestion: even if it doesn't work as-is, it provokes some thought about what behaviour we actually want to reward.
IOW, we are saying: "We hate most spolsky/coding horror/raganwald/..." posts, but from time to time there's a good one in there, so please ferret out the good stuff for us. Posting stuff from Paul Graham or Tech Crunch is not going to be rewarded.
Sounds suspiciously like re are rewarding risk-takers. That seems to be in the spirit of hacker news.
The next most easy option is to delay submissions by an hour or so. If two or more users submit the same URL in one hour then no-one gets credit. This would ensure that two or more bots monitoring the same blog would cancel each other. More generally, it would encourage more diverse content to be submitted.
A submitted article has high visibility and has no risk to karma. Contributing to a discussion has low visibility and risks karma. An RSS reader and a bookmarklet makes article submission semi-automated but insightful discussion takes more effort. Perhaps there should be more points for discussion.
I'm sorry, what problem are you solving here? The problem of a new user writing a bot and hogging the karma? While allowing an "old hand" to do exactly the same thing and reap the rewards?
Anyway, the reward of getting from karma 1 to karma R is greater than from R to R + hogging. If a user is past R karma and then decides to hog, then they're a moron and we should do something about that too.
No ideas, for the simple reason that I have a basic pessimism about trying to use carrots and sticks to create behaviour that is beneficial to a social group.
"We don't teach people to be nice, we hire nice people" --Leona Helmsley (sp?)
I think we can punish egregiously bad behaviour and we can moderate things, that eliminates outliers. But fundamentally our approach should be to encourage nice people to join and discourage trolls so that they leave.
It is not clear to me that karma is a good mechanism for that... if there is a game, some people will play for the sheer pleasure of winning.
I think the number one way to encourage nice people to use a social site responsibly is to swiftly and severly punish trolling. Nothing sends a message that you prefer signal over noise like banning noisemakers.
Let's turn this lemon into a shandy and figure out what to do about it.