The effects of any moderation system are to encourage what the moderators want and discourage what they don't. The norms on HN are very different from the norm

The effects of any moderation system are to encourage what the moderators want and discourage what they don't. The norms on HN are very different from the norms on Slashdot, and most of Reddit, which is why you get mature discussion here and not always elsewhere. You can see how the literal moderation system has not much to do with the type of discussion by going into some of the more heavily moderated Reddit subs. Believe it or not, there are lots of subs that are not full of jokes, puns, general unseriousness, and/or toxicity. It just depends on the crowd you attract (which is highly determined by the rules and moderation policy of the sub), what the moderators tolerate, and what they discourage.