The best content here is on posts that are years old, and discouraging discussion/engagement there would just make the current content problem worse.
To be sure, commenting on old posts is great. That definitely shouldn’t be banned. It’s not so clear about the karma system, which serves several functions, one of which is signalling “more like this” or “less like this” in varying degrees to users so that they can modify their commenting habits. For you and all those who value upvoting/downvoting old comments for its function of engaging with old conversations, perhaps there could be an alternative course between banning late votes and maintaining the status quo? For instance, the upvote/downvote buttons could still increment/decrement scores on comments after 30 days, but not the karma of the commenters. Since a commenter would still have to look back through their old posts to notice the change anyway, the signalling effect would remain unchanged from the status quo, but the possibility of using old posts to attack karma would be removed. (Downside: karma wouldn’t be the sum of comment scores.)
This doesn’t do anything to solve the problem of one mass-downvoter.
Right, the problem it was stated to mitigate is that “An attacker could still use multiple accounts to mass-downvote everything from a user in the past 30 days.” I forgot to state but also intended it as helping with the problem Ander brought up in the OP that getting a single comment massively downvoted has discouraged people from staying around LW.
Jiro correctly pointed out below that vigilence is the technologically simplest solution, albeit more laborious for everyone involved. My preference would be a community that prevented the problem rather than punished it afterwards. There’s no guarantee that there exists a rule that would be the perfect solution, but no doubt we can come up with simple rules that put trivial inconveniences (or nontrivial ones) in the way of undesirable behavior! There are probably many such imperfect-but-helpful rules.
To be sure, commenting on old posts is great. That definitely shouldn’t be banned. It’s not so clear about the karma system, which serves several functions, one of which is signalling “more like this” or “less like this” in varying degrees to users so that they can modify their commenting habits. For you and all those who value upvoting/downvoting old comments for its function of engaging with old conversations, perhaps there could be an alternative course between banning late votes and maintaining the status quo? For instance, the upvote/downvote buttons could still increment/decrement scores on comments after 30 days, but not the karma of the commenters. Since a commenter would still have to look back through their old posts to notice the change anyway, the signalling effect would remain unchanged from the status quo, but the possibility of using old posts to attack karma would be removed. (Downside: karma wouldn’t be the sum of comment scores.)
Right, the problem it was stated to mitigate is that “An attacker could still use multiple accounts to mass-downvote everything from a user in the past 30 days.” I forgot to state but also intended it as helping with the problem Ander brought up in the OP that getting a single comment massively downvoted has discouraged people from staying around LW.
Jiro correctly pointed out below that vigilence is the technologically simplest solution, albeit more laborious for everyone involved. My preference would be a community that prevented the problem rather than punished it afterwards. There’s no guarantee that there exists a rule that would be the perfect solution, but no doubt we can come up with simple rules that put trivial inconveniences (or nontrivial ones) in the way of undesirable behavior! There are probably many such imperfect-but-helpful rules.