Pornhub launched in 2007 according to Wikipedia. Mindgeek (Pornhub's owner) had a reported $460 mm in revenue in 2015. (https://www.luxtimes.lu/en/luxembourg/mindgeek-porn-empire-r...) Pornhub is privately owned, so how much of that $460 mm is Pornhub vs other properties is unknown, but Pornhub having made a billion dollars over its 14 years doesn't really seem that far fetched.

Digging a bit more, I don’t think so. The company that owns PornHub does about half a billion dollars per year in revenue: https://en.m.wikipedia.org/wiki/MindGeek

That includes revenue from other brands too, but I believe PornHub is their top brand, and likely accounts for a good portion of that. Also, how much money flows through PornHub that doesn’t count as revenue? I don’t know much about their business model, but say if a content creator generates $100 in total revenue on PH, and $40 goes to PH while $60 goes to the content creator, I’d guess that’s $100 in payments processed, but only $40 in MindGeek revenue?

Based on that, I’d estimate the volume of $$ flowing through PH at somewhere around $100,000,000-$1,000,000,000 annually. Even on the low end of that, around a billion should have flowed through them so far, over the lifetime of the site. And I think multiple billions is quite possible.

My knowledge is a little old (I was the CTO of a major porn site in the mid-2000s) but I would be willing to bet that most of Pornhub's income comes from affiliate fees, advertising, and other B2B transactions. These are not card transactions and do not go through payment processors.