After Google released the first version of its Penguin algorithm update in 2012, sites that had been practicing successful — but spammy — link-building tactics saw drastic ranking declines.

The depth and breadth of the post-Penguin fallout caused many to shy away from link building. Even though links were still being used to help determine search placement, the cost of being punished for an error was perceived as too high. And Google was hinting strongly that it was trying...