I think there's a bit of a self-fulfilling effect going on: readers know that stories by these sites do well on Hacker News, so when they see an interesting one that hasn't been published, they submit it.
I've seen this first hand: many of my blog posts are submitted to Hacker News shortly after I tweet them. Sometimes I know the submitter, and sometimes I have no idea who he/she is.
This of course is independent from what the article discusses. It's possible there are sites who make an effort to get hundreds of votes on HN but I doubt that's the case with TC, the NYTimes, etc.
I've seen this first hand: many of my blog posts are submitted to Hacker News shortly after I tweet them. Sometimes I know the submitter, and sometimes I have no idea who he/she is.
This of course is independent from what the article discusses. It's possible there are sites who make an effort to get hundreds of votes on HN but I doubt that's the case with TC, the NYTimes, etc.