I'm replying to this even though it was retracted, because it's an idea that I think needs to be discussed and I appreciate that you brought it up.
That said, I'm deeply skeptical that such a system would lead to less abuse, rather than more. I feel that karma systems should accurately convey information that is useful to the users, so I tend to be pretty touchy when I sense that they're being abused. Statements like "they're just meaningless numbers" indicates, to me, that a karma system is not performing its job correctly. Ideally, karma should convey several pieces of information, both to the audience and to the speaker:
I retracted it primarily because I read more of the thread and realized that the idea was too similar to another discussion which had already been brought up, which made the initial comment out of place and other parts repetitive. At that point, I was left with a "Since this has been brought up before, rather than posting it as a new idea, let me just retract it and upvote the other person who suggested it."
But that being said, I'm not sure I fully understand your abuse concerns. If someone wanted to abuse the system, they can just sockpuppet up ...
Several people posted recently in a thread on women, mostly espousing feminist views - only to find that someone had declined to respond to their post, but instead browsed their history and downvoted every single comment or article they had ever posted.
I have two questions:
1. Why would you come to a site like this and pollute the karma system? How does it make you smarter? How does it make anyone else on the site smarter?
2. What would be a good technical workaround? In my mind, some system that detects mass-downvoting and flags a user for review would be preferable, but what should happen then? Should the system be more lenient to higher-karma posters? Who should perform the review process? What should be done with those whom the reviewer ascertains are abusing the karma system? I would prefer some kind of lesson that is more corrective than retributive - it seems to me that people who would perform this behavior are exactly the sort of people who need some of the lessons that this site provides. Any ideas?