Dive summary: 

• Many publishers are indirectly benefiting from the popularity of online porn; because the digital world is mostly a numbers game, the popularity of internet porn has inspired many publishers to use that to their advantage. 
• A large percentage of publishers use porn-related keywords to drive traffic to their site.
• Not just publishers are guilty of using porn's popularity to their advantage, it happens with data too; widgets from AddThis, ShareThis and Twitter are popular on sites with adult material. 

From the article: 

"These sites could easily remove those pages from Google’s index if they wished, but they don’t because they continue to drive unique users, which enable them to tell more compelling stories to potential advertisers. After all, in the volume-driven digital ad game, bigger is not just better, it’s a necessity. According to some estimates, up to 15 percent of searches are porn-related. That’s a lot of potential eyeballs if you can find a way to appeal to them."