An investigation has uncovered that there are now more porn websites than there are real ones.
An online dictionary of porn has estimated that there were at least 1.6 billion porn sites as of October 2016, compared with around 1 billion for the real world.
According to data compiled by Pornhub, the porn industry was worth around $9.6bn in the US, $13.5bn in Australia and $17.5b worldwide in 2016.
The porn industry has become one of the biggest sources of revenue for websites such as Wix, which allows users to browse and rent adult content.
A report last year by the American Civil Liberties Union found that online porn businesses collected $927m in online advertising revenue in 2015, a 40 per cent increase over the previous year.
The American Center for Law and Justice (ACLJ), an organisation that represents internet freedom activists, has called for a crackdown on the online pornography industry.
“The porn business is not only the biggest source of illegal child pornography, it’s also the largest source of money to violent and criminal online abusers,” ACLJ deputy legal director Joshua Block said in a statement.
“This industry has a history of exploiting vulnerable children and its consumers for their own profit.”
The organisation has also launched a campaign, the Stop Online Piracy Act, which urges Congress to make it illegal for websites to profit from child pornography.
Last year, the US Senate passed an amendment to the USA Patriot Act, a controversial law that has been used to crack down on the internet.
It was opposed by porn sites and porn-industry lobbyists, who feared the amendment would force online pornography to stop operating.
Pornhub, which has a reputation for being one of best-known online porn destinations, has a strong following of users and businesses alike, with nearly a quarter of its users commenting on their website.
However, the firm said its site had recently seen a “very small increase” in traffic, mainly from users searching for the word “porn”.
“Our current traffic is consistent with our average traffic for the past year,” a Pornhub spokesperson told News24.
“In fact, we’ve seen our traffic increase even more recently than it did last year.”