What steps will reproduce the problem? 1. Pick someone you don't like 2. Downvote every article and comment they've ever posted 3. (if desired) Make a new account and repeat

What is the expected output? What do you see instead?

Expected output: Some kind of notice that you appear to be gaming the karma system for retributive purposes, rather than contributing to the site.

Instead: The system silently accepts your downvotes.

What version of which web browser are you using? On what operating system?

Please provide any additional information below.

Eliezer, do you have a preferred mechanism for dealing with this? (Asking you because you tend to want to have a say in LW code changes.)

I'd as soon silently reject the downvotes and notify a moderator, who could then either approve, or remove downvoting ability (still with silent rejection) but that would be way more complicated. As it stands, just vanishing the downvoting buttons on that user after -10 karma in 1 day sounds reasonable. We also want to allow this when the downvoter has more than 1000 karma and the user has less than 70% upvotes, maybe - there are such things as trolls.

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One objection to this: in my case, for example, I came to the attention of someone very quickly in my career at LW, and they have made sure to keep me below 68% upvotes consistently.

If I may be so bold, I think the proper solution is to record the name and timestamp of upvotes/downvotes with the upvote/downvote itself, and signal a flag to a moderator if more than, say, 50% of a person's dkarma/dt within a particular span of time comes from a particular person. Put in a threshold so that low-karma edge cases don't trip false positives, and have the moderator review all karma to see if someone is either downvoting retributively, or upvoting collusively.

If we use fairly tight criteria for when to notify a moderator, it won't take that much time on their part. It would also be helpful if whatever bug fix we use also works retroactively so the moderators can see what has been happening up until this point, but that's not strictly speaking necessary.

I don't think that using the downvote's curent karma total is a good idea as a standard. In practice almost any serious block downvoting will occur from users with some karma anyways.

This has just happened to me (Jiro). I tried to private message Eliezer but he didn't respond--he's probably swamped with responses to all the stuff he writes.

I went down by 50 karma in a week or so and the damage is only this light because every so often I beg and other people mod some of my recent comments up again. Checking my comments shows that of the past 100 comments I've made, exactly one was not downvoted, which is not only extreme, it clearly indicates a downvote by exactly one person, since the same number of downvotes made by multiple people would be distributed in a more random manner. Statistically speaking, distributing 100 random down votes should result in about 35 comments that don't get any downvotes (of course that's a simplification, since there are also legitimately downvoted comments, and upvotes, and it's not always possible to exactly determine the number of votes from the count without a lot of work).

At the rate I'm losing karma, I will be forced out of LW by August (if the downvoter bothers to create extra accounts to continue downvoting at the same pace).

And it's not fast enough for the downvoter to be discouraged by only voting down -10 per day. It's only averaged around that on me.

Also, I've already been taken below 70% by this, so basing it on whether the victim is below 70% is not good.

The simplest fix would be to show the names of everyone who downvotes you. Anyone who finds that 99 comments out of 100 have the same person's name listed as a downvoter could easily expose them.

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I'm now down to 515 karma, having started with 605.

The moderators are being seriously amiss in refusing to look at this or do anything about it.

One user responsible for systematic downvoting [http://lesswrong.com/r/discussion/lw/kfq/moderator_action_eugine_nier_is_now_banned_for/ seems to have been caught], though there are still [http://lesswrong.com/lw/kfn/moderators_please_wake_up_and_start_protecting/b26e no tools] in LW's interface that would simplify solving similar problems in the future. Not clear if the attack on user MugaSofer reported in issue 382 was investigated.

Apparently, it's not currently hard for Trike to investigate particular cases, so posting the quote here for future reference:

http://lesswrong.com/r/discussion/lw/kbk/meta_policy_for_dealing_with_users/

"For future reference, it's very easy for Trike to look at who downvoted someone's account, so if you get questions about downvoting in the future I can run the same report." -- Jack from Trike aka user jackk on LW http://lesswrong.com/user/jackk/