I'd really like a downvote on articles, although it's a tricky decision I guess.
Up/down votes on comments should be, in my view, for whether you thought the comment was worth reading or not, irrespective of viewpoint. Likewise for upvotes on stories.
I'm kidding, but I've been dishing out karma lately, if I even so much as agree slightly with someone, or think that their viewpoint is slightly interesting/relevant.
edit: I suspect that the person that downmodded me has no sense of humour :)
I now appreciate down votes and see it as a way for the community to 'teach me' (not in a negative way par se but as a guiding/helping hand) in the simplest way possible.
:)
If users really shouldn't care about their karma, would the site be served better by not making karma visible at all, for users or for comments? You could keep upvotes and downvotes, and even let users know their own karma and how their own comments are rated (so they know when their contributions are being rewarded), but their would be no high-score table of top users, and users would only be able to guess at a post or a comments karma based on where it appears on the page.
This would take away the motivation some people have to contribute high-quality comments - I'm not sure whether the net result would be positive or negative.
Part of this discussion needs to include a serious discussion of what this site's core goals are. If this site were a web startup that needed to get high traffic, than a game-like system that gets posters addicted to writing comments to try and boost their karma makes sense. If the site is more about making sure it has the highest quality content possible for its original niche target audience, than that would make this approach less appropriate.
I have learned to stay away from political discussions. Ouch!
There was a post about the birthday of the user edw159. Some people thought that the post wasn't hacker "newsworthy" and others thought it was ok. I commented "I think edw159 is one of the more active members and recognizing his birthday is ok" and I was downvoted pretty far. I think my comment was appropriate and it added meaningfully to the conversation, but a lot of people downvoted it to (I assume) show their disagreement.
Now I'm worried before I post any comments, partly because I'm worried I'll lose my precious karma but mostly because it's embarrassing to have a negative number next to one of your comments.