The operator of a revenge porn website has been sentenced to 18 years in prison, in what is being described as the first criminal prosecution in the U.S. of the operator of a website of this type.

Kevin Christopher Bollaert, 27, of San Diego, was found guilty in February this year on six counts of extortion and 21 counts of identity theft, California's Attorney General Kamala D. Harris said in a statement. He was arrested in December 2013.

U.S. regulators have started clamping down on revenge porn, which generally consists of the posting of nude photos and other explicit content of users without their permission, and then blackmailing them for payment to take it down.

The Federal Trade Commission in January charged Craig Brittain, the operator of a website isanybodydown.com, for allegedly charging women between $200 and $500 to have their images and personal information deleted from the site. The images were obtained under false pretenses.

Under the terms of a settlement with the FTC, its first case against a revenge porn site, Brittain was required to permanently delete all the images and other personal information he received during the time he operated the site.

Bollaert similarly extorted fees ranging from $250 to $350 from affected women with the promise that the compromising content would be removed, according to Harris.

His website ugotposted.com required that the poster include the subject's full name, location, age and Facebook profile link, resulting in severe harassment to the victims on social media, at places of work and in their communities, she added.

Casey E. Meyering, 28, of Tulsa, Oklahoma, the alleged owner and operator of another revenge porn website, was arrested in February last year by agents of Harris' e-crime unit. He was charged with five felony extortion counts and is awaiting trial on June 8.

John Ribeiro covers outsourcing and general technology breaking news from India for The IDG News Service. Follow John on Twitter at @Johnribeiro. John's e-mail address is john_ribeiro@idg.com