So my genuine question - asking if this post (an advertisement for AdGuard) is within HN rules - got flagged. I've since checked the guidelines and while it doesn't explicitly say product placement posts are verboten, they do seem against the spirit of the site ("Please don't use HN primarily for promotion"). But what guideline makes my comment flaggable?
Users flagged it as well as https://news.ycombinator.com/item?id=32554218. We can only guess why users flag things, but in this case I think they probably just thought the comment was off topic, and not in an interesting way.
The key for whether an article is good for HN is not its "adiness" (if I can put it that way) but its interestingness - i.e. does it gratify intellectual curiosity. In this case plenty of users clearly thought it did. It may be true that an article was written as part of a startup's effort to promote its product, but that's not necessarily a bad thing, as long as the content itself is interesting. (Of course, it tends not to be, because content marketing tends to be boring, but that's a different issue.)
