Hmm. HN likes substantive articles and dislikes sketchy tactics. Those two almost never conflict. When they do, though, we tend to favor the substantive article, which this one clearly is. It's an elementary tutorial, yes, but an unusually well-crafted one, and had it appeared on the author's website (http://apfelmus.nfshost.com/blog.html), there'd be no question.

Perhaps the positive reinforcement of seeing what actually works to get on the HN front page—solid content—will combine with earlier negative reinforcement—prior sketchy tactics have gotten this site penalized—to induce a change in behavior. I know that sounds unicorny, but the last time something like this came up on HN, a different site actually cleaned up its ways. Maybe lightning will strike twice.