And of course you can just retract all your posts to avoid having them downvoted. They are still readable through the cross-out lines. And people can still respond to them with comments. A nice back-door way to opt out of the karma system?

I'm replying to this even though it was retracted, because it's an idea that I think needs to be discussed and I appreciate that you brought it up.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: 1. How the audience feels about the speaker's specific comment (this is the most important) 2. Why the audience feels that way about the speaker's specific comment (this is almost as important as 1) 3. How the audience feels about the speaker in general (this is the most problematic piece of information, because all of the primate pack dynamic instincts come rushing in) 4. What the speaker should work on to improve themselves (this is very difficult to convey, because all the problems that cause 3 to fail are amplified when applied to 4).