I suspect, though, that there isn't a ton of competition for the keywords that matter to them. So the boost you get from hitting HN/TC/whatever once a month mi

I suspect, though, that there isn't a ton of competition for the keywords that matter to them. So the boost you get from hitting HN/TC/whatever once a month might be enough to keep them at the top of Google's SERPs. They did say that SEO drives something like 90% of their business.