Life is short. Have an affair, urges AshleyMadison.com, a social networking site for married people looking for extracurricular love. Visit for an "erotic chat" or meet up for "anything goes."
On gay.com, check out "Cronic-Candy," a 22-year-old California man who is looking for a hook-up and insists, "I'm not gay, guys just like sleeping with me."
On Craigslist.org, sex-seekers can go "preference shopping" for sex with or without a condom on the site's "casual encounters" or "men seeking men" pages, where escorts and sex workers cruise the Internet's so-called "erotic underbelly."
Social networking sites connect friends, serve special interest groups and make it easier than ever before to stay in touch.
But when the Internet is used for anonymous and unprotected sex -- that touch can turn toxic.
Such was the case with Brett, now a 21-year-old college student who met up with men at a party through a connection his friend had made online.
"It was one of the few times I had unprotected sex," Brett, who asked that his last name not be used for this story, told ABCNews.com. "But my friend and I were still in high school and these guys were older and we had been drinking."
Today, after Brett's reckless encounter he is HIV positive.
"A lot of people don't like to use protection," said Brett, who lives in Chicago and was diagnosed when he was 18.
Some fear that online chat rooms and dating sites are becoming today's virtual bathhouses, where HIV/AIDS first percolated among gay men in the 1980s.
On April 28, the Kaiser Family Foundation will release a report that finds the number of Americans who list the disease as "the most urgent health problem" is at its lowest levels ever -- only 6 percent, compared to 44 percent in 1995.
That report comes on the heels of one from the Centers for Disease Control and Prevention that found the number of Americans newly infected with HIV/AIDS is 40 percent higher than previously reported -- 56,300.
More than 1 million in the U.S. are living with the disease, and 14,000 to 15,000 die annually.
"The epidemic has been roughly stable since the late 1990s," according to the CDC, though the numbers remain "unacceptably high."
More than one-quarter of HIV-infected people are unaware of their infections, according to the CDC. And more new infections occur among young people ages 13 to 29 than any other age group -- precisely the demographic that uses the Internet for social networking.
An estimated 16 million people say they have used Web sites to meet other people, according to report prepared by the Pew Internet and American Life Project.
Gay men, in particular, have benefited from the "privacy" of the Internet, with 40 percent reporting they use it to find sex partners, according to studies cited by the University of California San Francisco AIDS Research Institute.
Their studies reveal that people who use the Internet to meet sexual partners engage in more risky behavior: they have more partners and are more likely to report sexually transmitted diseases than those who seek sex in more traditional ways.
"These sites are a great temptation for those who suffer from sexual addiction," said Dr. Kristen Ries, an infectious disease specialist from University of Utah Hospitals and Clinics. "I am especially worried about some of the younger generations who are so Internet savvy, but who seem nonchalant about the seriousness of HIV/AIDS."
"Remember that HIV positive people who are in denial about their HIV, or who are fearful of abandonment if they disclose their HIV positive status, are more apt to seek anonymous sex at such sites," she told ABCNews.com.
With that in mind, many public health agencies are using the Internet to change people's attitudes and educate them about the possible dangers of risky sex.
Some studies have not found the Internet to be inherently more dangerous than bars and dance clubs.
"We haven't seen a huge difference in the risk when sexual partners] are recruited in online rather than other venues," said Greg Rebchook, a researcher at CAPS.
But the center acknowledges that using the Internet to meet sexual partners "creates an environment" where high-risk and low-risk sexual partnering occurs and can increase the transmission of HIV.
Blacks and Latinos account for the largest numbers of new infections (45 percent and 17 percent respectively), according to the CDC, which suggests the cultural shame associated with homosexuality prevents them from seeking or disclosing their status.
"Men who want high risk sex will find it, especially in an urban environment, whether they do so face to face or online," said Dr. Demetre Daskalakis, founder of the Men's Sexual Health Project at New York University.
"Rather than demonize social networking sites as drivers of the epidemic, we should look more to the root causes of homophobia and hate that generate shame and self-destructive behavior."
After Brett's reckless encounter, he and his friend found Chicago's Howard Brown Health Center online and arranged for free testing. Both are now undergoing treatment.
"I think finding out you are HIV positive makes you grow up a lot faster," said Brett, who graduates with a degree in interior design from Chicago's Harrington School in May.
"A lot of people don't like to use protection," he said. "Some people think if, 'I don't know about it, fine.' But once I found out I was positive, you make sure that you are using protection all the time, and I make sure my friends are."
Public health professionals are turning to social networks as a tool to combat the high numbers of HIV/AIDS infection.
"The whole idea of preventing HIV/AIDS is getting ahead of it," said Jen Kates, vice president of HIV policy for the Kaiser Family Foundation, which is using the Internet to bring more attention to HIV/AIDS. "You anticipate the forums where people meet."
Kaiser worked with MTV's 24-hour college network to develop "Poz or Not," an online game that challenges stereotypes and breaks down the barriers that may prevent people from talking openly about HIV/AIDS, getting tested and using protection.
The "GYT" (Get Yourself Tested) campaign was created under a partnership with MTV, the Planned Parenthood Federation of America, CDC and others to increase testing for those under 25, using a Facebook application.
"A few years ago we had concerns about chat rooms and hooking up, but now are turning it on its head and using social networks for educational purposes," Kates said.
Craigslist.org has agreed to add a health message and link to the San Francisco City Clinic site on its "casual encounters" and "men seeking men" pages. AshleyMadison.com also posts an safe sex education forum.
"We became convinced that friends can be good medicine, and if we are able to increase the conversations in social networks about HIV, it can have a positive effect in decreasing the rate of infection," said Steve Morin, director of the Center for AIDS Prevention Studies (CAPS), which also worked with gay.com to post an "Ask Dr. K" forum.
Using the Internet to notify partners is also becoming "standard practice" in public health, according to Morin.
Manhunt.com, with about 4 million active profiles, was the first dating site to address sexual health in 2002 with partner notification, outreach and research services on its Manhunt Cares page. Its directory lists hundreds of health clinics around the world where men can get face-to-face help.
"Manhunt has been an industry leader," said David S. Novak, a former CDC coordinator who heads up Manhunt Cares. "We are hoping to pressure Facebook and MySpace to create health profiles of their own because so many of the infections are with young kids. They can show us up, compete with us."
ISIS, an organization that finds technology solutions for sexual health, sponsors Inspot.org, where those who are HIV positive can send anonymous "e-cards" to notify up to six sex partners in 11 cities and three languages.
"It lets you know if you've been exposed and links you back to testing and resources," said ISIS Executive Director Deb Levine. "The social network mobile community is here to stay. This is not something we can ignore and it will go away. It's very much a part of our lives."
The Chicago's Howard Brown Health Center, where Brett sought help, has created active profiles on numerous sites, such as Facebook, Adam4Adam, Barkackrt and MySpace, to help those who are infected to contact their sexual partners.
The clinic also does proactive outreach on 30 other sites to raise awareness. According to Daniel Polner, the clinic's manager of disease intervention, social networking sites are less anonymous that the traditional venues where gay men gathered.
"In the bathhouses and bookstores the culture is not to ask the name," Polner told ABCNews.com. "But online you have a screen name or a buddy list or, on Craigslist, you can trace a person's e-mails."
"Some people call it anonymous, but it's not," he said. "There's a way to reach the person."
Just this week, in an unrelated incident, police were able to track the suspect in the so-called Craiglist killing in Boston through the e-mails he sent to a masseuse.
"I know it sounds very Pollyanna," said Polner. "But the one thing we always say is, it's not who you meet and where you meet them, it's what you do. The person makes the decision to wear a condom, and in many of those [Internet] situations, they are less likely to be drunk. Whatever their decision, it's more intentional."
Meanwhile, Brett has joined Howard Brown's board, and is taking good care of himself, preferring to make contact with his sex partners the old-fashioned way -- in person.
He still has accounts with gay dating sites, but said, "I don't use it for one night stands, and my profile says 'Do not contact for hook-ups."
"It definitely has become a bathhouse," he said of social networking. "Everyone I know has Manhunt or Adam4Adam, even my friends. It's really sad, even with Facebook, that we go online and meet these people and rely on the Internet rather than engage in person."
"If I meet someone in public, chances are I am with someone who knows something about them and give you a little more information."