A US man has been charged with operating a website that let people anonymously post explicit photographs of others so he could extort hundreds of dollars from the victims.

Kevin Christopher Bollaert, 27, from San Diego, was arrested on 31 counts of conspiracy, identity theft and extortion.

Bollaert created the so-called "revenge porn" website ugotposted.com a year ago, according to court documents. The site let people anonymously post more than 10,000 nude and explicit photographs of others without their permission, investigators said.

Unlike most such sites, investigators said ugotposted.com required that the victim be identified by name, age and other information, leading to the identity theft allegations. He is charged with obtaining identifying information with the intent to annoy or harass.

Bollaert was released from jail after posting 50,000 dollars (£30,000) bail. He is set to appear in court on December 17.

The documents say Bollaert charged victims a fee between 249.99 and 350 dollars to remove the images, using emails sent through a second website, changemyreputation.com. That led to the extortion charges.

Both websites have been closed down.

His activities "turned their public humiliation and betrayal into a commodity with the potential to devastate lives", attorney general Kamala Harris said in a statement.

Bollaer told investigators during a six-month investigation that he received about 900 dollars each month from online advertising. However, the department said records from his changemyreputation.com PayPal account show that he received tens of thousands of dollars.

Photographs used as revenge porn can be obtained during a consensual relationship, investigators said, or can be stolen or hacked from online accounts. The practice resulted in a new California law that makes it a misdemeanour to post identifiable nude pictures of someone else online without their permission and with the intent of causing serious emotional distress or humiliation, though that law was not cited in the charges against Bollaert.