Hacker News biases it algorithm to favor external links (according to a tweet awhile ago by pg that I can't find). @kr and I discussed this recently. It's like the difference between an inside joke and one that's appealing more generally. It also lines up with dang's thoughts on what makes for interesting internet discussions, specifically that "generic discussion is not interesting, at least not on internet forums."

These days there should probably be some demotion for links to paywalls and trackers and pages with ads, favoring personal blogs and the small web.