Now HN is a mix of tech news and politics, and I'm not surprised that some HN readers who are not interested in startups have no clue what YC is about.
The few tech stories that do make it through are far more pop-tech article (right now NPR, BBC, New York Times, MSN, and Haaretz are all on the front page... absolutely nothing to do with hackers or gratifying intellectual curiosity) or talking about startups that are shutting down.
I'm tired of collapsing the inevitable "Macbooks are bad" thread and finding out that was literally the only conversation under the article. I think the mods do a great job of keeping the conversation civil, but a poor job of enforcing "intellectual curiosity" like the guidelines call for.
That's mostly true. It doesn't seem to be mentioned anywhere and is not very well-known, but dang maintains hnreplies.com, an email notification service for HN. Apparently only 1860 users are signed up, but it's there.
In general, I agree with your advice. Very often I get halfway through writing a comment, but delete it because I don't think it will spawn useful conversation or be appreciated, whether it's because I'm being needlessly argumentative, or the person I'm replying to is.
...until recently, when I discovered that the website has a way to list your comments and their replies. Since then I've been using the website more, and I don't like how it's changed my engagement patterns. More looking at and thinking about karma, more replying to someone just because they replied to me. I guess generally more "social", in the bad (for me), human-level meta communication (ego, drama, etc), instead of with the more interesting content / ideas.