I think if folks here (or the public in general) knew how common this was, they'd be shocked and outraged. I can say with quite a bit of conviction, experience

I think if folks here (or the public in general) knew how common this was, they'd be shocked and outraged. I can say with quite a bit of conviction, experience and data that this is incredibly common - even overwhelmingly so. My conservative guess is that for 50-100K+ keyword searches where substantive commercial value exists in ranking well, 50%+ of the top 10 ranking pages have engaged in manipulative link practices. They're not usually this blatant (though plenty are), but penalization is rare and link spam is on the rise. My sense is that rather than try to write algorithms to compensate, Google's webspam team has been focused on finding less manipulatable signals like social data (which is currently relatively clean), user+usage data (through Chrome, GG toolbar, GG analytics, etc) and more sophisticated citation analysis. Still, it's hard to preach white hat SEO when black hat works so frequently and so well (and from outward appearances, Google rewards it).