tl;dr: maintaining an online community is anything but simple.
I'm not sure exactly what you mean. One possibility is that you're referring to the hackers that build communities online who try to establish some sort of guidelines for behavior.
If this is what you meant then I think I disagree. I've tried a very similar experiment to pg's with HN. I run a small community site http://yakkstr.com and most of the users came from an older site called soulcast. soulcast had no rules and it degenerated exactly as expected and was full of trolls in no time. My entire goal was to recreate that site minus the trolls, and I ruthlessly enforced one simple rule. Do not directly insult other users of the site. (actually two rules: no porn, illegal stuff, or spam)
Simple right? Not really. I loved pg's child metaphor, and just like a child the trolls from the old site, who are smarter than actual children, do everything they can to find the limits to what is allowed, and they hover right around that line. As soon as they think you're going easy they push it farther.
One example, people like to argue about politics on yakkstr and one of the trolls uses a pattern of associating a label like "liberal" to someone then they insult the label. Moronic ideas for liberals, liberals are morons, etc, etc. Technically he's not violating my rule, but it's very hard to define an explicit rule to deal with such instances because you want to allow people to sometimes say controversial things about generic groups.
The problem arises when someone gets offended and reacts by directly insulting the savy troll. How do you deal with it? Not so easy. And occasionally a good user gets made at something and calls someone a moron. It leaves a bad taste in their mouth if you come down with an iron fist on them.
I don't have good answers to these problems, but I think the hard work is working out pretty well for my little community. But it is complicated and requires constant vigilance.