A working karma system, where low-quality contributions get downvoted, would mitigate this. Maybe the concern is that a large influx of people would degrade the quality of voting, but there are ways around that. Not letting new users vote for a while would work, but it would be pretty heavy-handed. Maybe there's a non-heavy-handed solution that also works.
It would mitigate it, but it's not getting at what I'm really talking about. Our equivalent of Wikipedia's vandalism isn't the issue - downvotes suffice for that.
What I mean is in general the flood of people not familiar with the existing material, not reading it, asking old questions, engaging in half-arsed arguments, misinforming others, etc. A handful can be educated by the regular they run into; if 1 newbie replies cluelessly to an old comment or post of mine, I can take the time to dig up the links and refute/educate them. If 100 newbies do that to me...
Recently reporters from two major national magazines contacted me in preparation for doing stories on Bitcoin. This reminded me that Wired magazine did a cover story on the Cypherpunks in its second issue. I think the LessWrong community is already larger and more active than Cypherpunks were back then, and potentially more influential, but there hasn't been much publicity on us. I'm tempted to suggest doing a story on LessWrong to one of the reporters. Is this a good idea, or bad?
More generally, do we want more publicity, and if so what's the best way to go about getting it?
ETA: Would it be bad etiquette to reveal the names of these magazines at this point, or even to say as much as I've said?