That reminds me of a feature of 4chan, where there is no archive and every conversation is deleted after it becomes inactive. (This has been circumvented by other websites that archive 4chan threads, but not all of them get archived). I like being able to discuss ideas like this without ruining a website's reputation (though 4chan isn't a perfect analogy, because it discusses awful stuff so often that even if you can't find it on Google, it's reputation is terrible). Maybe LW should have something similar? Maybe you should be able create a thread that can only be viewed by people with >N karma? Or that, after so much time, will become viewable only by people with >N karma?