[einhverfr]

I have watched posts of my own go upvoted then downvoted then up voted then down voted more or less randomly.

FWIW I do NOT think people should downvote based on disagreement. I think downvotes should be sparsely used and I personally upvote even people I disagree with.

[gbog]

Well, maybe, but now I am using thread upvote mostly to promote themes I like to see on HN, and comment downvotes to push down thanks, me-too, or otherwise empty answers.