The latest website rankings in the United States show Americans spend a lot of time checking out porn, with three of the top eight spots occupied by adult entertainment sites.

What are the details?

The Daily Caller reported that there are only five websites used by Americans more than Pornhub: Google, YouTube, Facebook, Amazon, and Yahoo. The rankings were compiled by SimilarWeb, and showed Pornhub's No. 6 spot was followed by adult website XNXX.com at No. 7, and yet another porn site, XVideos, at No. 8.

Ebay, Twitter, Wikipedia and Instagram followed — in that order — with Reddit, Craig's List, Bing and Live.com also coming in ahead of porn site XHamster.com, which beat Netflix by ranking No. 17 on the list.

Pornhub's popularity is well known. The site averages 90 millions users per day, and monitors the rise and fall of its traffic with major cultural events. But according to The Caller's David Hookstead, the ranking of porn sites "coming in this high might be a shade unexpected."

Yet, America's internet habits aren't all that different from the rest of the world. SimilarWeb showed Google, YouTube, and Facebook were also in the top three spots when accounting for users around the world. No. 4 on the worldwide list was a search engine called Baidu, followed by Instagram and Twitter. Pornhub was No. 7, Yahoo No. 8, and XVideos was No. 9.

Anything else?

According to a piece written by David Kushner in Wired, the popularity of internet porn isn't all that shocking. Erotic images have "emerged, predictably, with every new technological advent," he explained, noting such depictions have been shared by humans for tens of thousands of years — with the ancients using mediums like cave drawings and clay tablets.

Kushner gives a history of how the modern porn industry has grown into a multibillion-dollar business, which has been fueled by continuous innovations, content, and online advertising.

"For better or worse," he says, "online porn [is] here to stay."