LONDON (Reuters) - Be careful who you fall for this Valentine's Day -- they may just splash your most intimate secrets across the Internet.
Thousands of people around the world have started personal Internet journals or "blogs" which expose the sort of details of their sex lives that would make Bridget Jones blush.
While explicit diaries are nothing new, technology allows stories of sex with strangers, workmates or old flames to be shared with the rest of the world in seconds.
"I don't think talking about sex is anything new -- only the medium has changed," said Abby Lee, one of Britain's best known sex bloggers. "The Internet offers an easily accessible way to read and write about sex."
Blogs -- short for Web Logs -- are personal Web sites where people publish their diaries or thoughts, talk about current affairs or link to other stories or pictures on the Internet.
Blog tracking Web site Technorati lists nearly 7 million sex-related blogs.
Their rise has sparked a legal, ethical and moral debate that pits free speech against the right to privacy of those who, perhaps unwittingly, feature in these blogs.
American blogger Jessica Cutler faced legal action in the United States after being exposed as the author of a blog detailing her steamy liaisons with six men while working as a junior aide to a senator.
Cutler, who wrote as the Washingtonienne, was sued for invasion of privacy by one of the men she wrote about. After being sacked, she wrote a book about her exploits on Capitol Hill and posed for Playboy magazine.
"It is amazing to me that people have any interest in such a low-level sex scandal," she told the Washington Post in an interview. "It's like: 'There's a slutty girl on the Hill?' There's millions of them."
The freedom to use a blog to express any opinion is a mixed blessing, according to psychologist Dr Petra Boynton.
"You don't quite know if someone you meet is going to be blogging about it," she said. "There are no guidelines or books that tell you the right way to do it."
Writers must balance the need to protect people's identities, while keeping the blogs real, Lee said.
"I worked hard to disguise others' identities," she said. "I didn't have to worry about their knowing I had written about them, or how I might be judged, or be forced to face inevitable sexist labelling because I am female."
In China, a supposedly British blogger who bragged about seducing women in Shanghai sparked an angry response, with visitors to the site demanding he be deported.
The identity of the author, known as "Chinabounder", remained shrouded in mystery, with some newspapers claiming the whole thing was a stunt.
Some religious groups say blogs are a powerful tool that can be misused. Children who use them could be targeted by paedophiles, the Restored Church of God warns on its Web site.
"Another obvious danger of blogs is the endless amount of inappropriate content often spread throughout them," it says.
But for those who write them, they are a harmless outlet that can entertain, educate or offer an alternative view of sex to that portrayed in traditional media outlets.
"We are much too emotionally repressed in society," said Lee, whose real name is Zoe Margolis. "Sex blogs offer people the opportunity to express themselves.
Her blog (www.girlwithaonetrackmind.blogspot.com), one of several explicit Web diaries to be published as a book, offers a "non-sexist, feminist" view of sex the media ignores, she added.
Another blogger, Belle de Jour, whose site (www.belledejour.co.uk) purports to chronicle her work as a London prostitute, said society has become more broad-minded.
"I don't believe there is a single person in Europe or North America under the age of 60 who actually regards such things as private any more," she said in an email interview.
"The appeal to me was of having an anonymous place to write about the things that were happening to me as a sex worker."
She accepts that it could be disloyal to spill the beans on a former partner, but asks: "Has that ever stopped people from chatting over the garden fence? Of course not."
Writing about the minutiae of your sex life gives an illicit thrill and is another form of exhibitionism, according to Sarah Hedley, the British author of sex manual "Sex by Numbers".
"The only thing a person needs to sustain a blog is an Internet connection, a basic ability to write and a healthy sexual appetite or an active imagination," she said. "Not everything you read in blogs is true."
However, sex blogs can be used in a positive way to educate people in developing countries about sexual health or broach areas that get less publicity, such as the sex lives of older people and those with disabilities, Dr Boynton said.
"It did begin with a few people talking about their kinks and fetishes, but has escalated way, way beyond that," she said.
The next step will be the wider use of blogs by companies pushing sex products from pharmaceuticals to sex toys, she said.
But, she added, the rise of sex blogs doesn't necessarily mean people are having more or better sex.
"We're actually having about the same amount of sex and we've got more problems and worries than our grandparents," Boynton said.