I would be surprised if there wasn't an overlap between HN and 4chan (same as with SA). Being run in diametrically opposed way it fills its role rather well, I think. There is no reputation system, no limits, no censorship, etc.. This means it produces many utterly vile posts - but all of them are true expressions of people as they are, not as they pretend to be. I think people often don't appreciate this. It's not j…
A vast majority of the vile posts are people playing a game/acting out a character/aping (along with) the community. It's willfully not-in-earnest. It's crazy that people think 4chan is 'true expression'.
That's not to say that there's not truth in 4chan, it's just that it's not on the surface, it's 'another layer down'.
For example, take /fit/, the fitness board. It's full of great advice and discussion... as long as you know enough to read past the obvious bad advice that's willfully posted to fuck with people.