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.
If the LW community cares about this issue, then they should just petition an admin to check who is doing the downvoting. There is a log of "liked" and "disliked" which is available. They could even set "dislikes" to public. Even in the event that the retributive downvoter uses a puppet account to downvote, we can still automatically prevent accounts from selectively downvoting all a users posts.
There's absolutely no reason to guess at naming specific people and starting a witch hunt. Since the person didn't necessarily use a sockpuppet, there may is an easy way to know for sure who is doing this if we are willing to do just a little extra waiting and petitioning the mods.
I say this as one of the people who has been block downvoted. Even discounting the chance of ialdabaoth naming the wrong name, I doubt that the act of naming someone has a better expected outcome than the act of not naming someone. It sets a bad precedent and makes the community vulnerable to all sorts of social exploits in the future. In particular, since downvote sources are hidden, framing is completely trivial to do.
(I realize the admins haven't done anything about the issue in the past, but despite that this is still the course of action I would advocate.)
Anyway, it's too late for ialdabaoth to not name his/her suspicions. As we have already seen, it has had an adverse outcome regardless of whether his/her guess (which even s/he put at only p>.75) was correct and has led to more abuse of the voting system. Downvoting as retribution against retributive down-voting is dumb because retributive downvoters can simply take alt. accounts and continue what they were doing.
However, we can still petition the admins to check the records / make downvoting public / put in automated measures / etc.. We can still not do this "guessing" thing next time. We can still create a informal rule against calling people out for things despite low certainty.