A dot product is really damned hard?
I would expect the karma evaluation to be encapsulated. It would need to be rewritten to take a personal configuration that is editable, and then the calculation would need to be changed to run the dot product of the configuration and the votes. That doesn't seem that hard.
Probably creating the configurable karma weighting would be the majority of the code changes, while the change in calculation would be a few lines.
To clarify, my claim was that it would be really damn hard to do this while keeping page loading times reasonable. I'm less confident of that than I used to be though.
I also object that there are privacy implications; but full disclosure, I think my true rejection is just that this idea strikes me as... ugly, I guess.
I'm just tired of the signal pollution, and would like to be able to use karma to honestly appraise the worth of my articles and posts, without seeing 80% of my downvotes come in chunks that correspond precisely to how many posts I've made since the last massive downvote spree.
EDIT to add data points:
Spurious downvoting stopped soon after I named a particular individual (not ALL downvoting stopped, but the downvotes I got all seemed on-the-level.)
One block of potentially spurious downvoting occurred approximately one week ago, but then karma patterns returned to expected levels. I consider this block dubious, because it reasonably matches what I'd expect to see if someone noticed several of my posts together and disagreed with all of them, and did not match the usual pattern of starting with the earliest or latest post that I had made and downvoting everything (it downvoted all posts in a few threads, but not in other threads), so I'm just adding for completeness.
Spurious, indiscriminate downvoting started up again approximately half an hour ago on Sunday (12/1/2013), around noon MDT.
Edit: And now on Tuesday, 12/3/2013, at 10 AM, I'm watching my karma go down again... about 30 points so far.
Edit: And now on Saturday, 12/14/2013, at 2 PM, I'm watching my karma go down again... about 15 points so far, at a rate of about 1-2 points per second.