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.
I am part of a community. Karma is a signaling process used in that community. I can participate, on many meta-levels, in the evolution of that signaling process. I am choosing to do so, because it is my wish that karma be an accurate signal for the worth of a particular line of discussion.
I.e.: to me, positive karma should mean that the post contributes to either the poster's or the the community's understanding of rationality; negative karma should mean that the post interferes with either the poster's or the community's understanding of rationality. A high karma post should mean "people should read this entire thread; it leads to a particularly useful realization", while a low karma post should mean "this entire mess is an appeal to various easily-stimulated cognitive biases".
When Karma is used to silence people because of things they said in an unrelated discussion, or social or political goals they have admitted to having, then karma is no longer serving the explicit meta-goal of lesswrong.com.
If I'm saying something terribly low-signal, downvote it. If I'm saying something particularly noteworthy or insightful, upvote it. But if I'm a guy that once got in a fight with you about human rights, don't downvote a philosophical discussion I'm having about identity five months later, if you actually care about the lesswrong.com community at all. Find some other way to destroy your enemies.