Craigslist: Anything You Want... Anytime

"It's the oldest profession in the world and there'll always be demand for it. You know the Internet is being used to feed that," says a woman who calls herself, "Kelly."

Kelly is an erotic masseuse in Manhattan. She says her husband never knew. 48 Hours Mystery agreed to protect her identity.

"I give massage for men," she says. "From head to toe." The 30-year-old aspiring actress admits, sometimes, it even goes further.

"I knew I could make two or three times more money than I was making if I had my top off and I gave a sexual release," she tells 48 Hours Mystery correspondent Harold Dow.

"Is that where the money is?" he asks. "Totally. That's completely where the money is," Kelly replies.

And when she put a massage ad on Craigslist two years ago, the business really started booming - to the tune of up to $1,000 a day. "I personally think it's the best place to advertise," she says.

Still, Kelly says, she plays it safe by screening her potential clients on Google and listening to her gut. "I think I can have a sense about a person within 5 seconds of hearing their voice. If I have any, slightest doubt, I will not see that person."

Julissa Brisman may not have seen any warning signs in the behavior of Philip Markoff.

"You've obviously heard about this murder that occurred with someone who used Craigslist to advertise. Do you think about it? Are you worried about it? Are you afraid?" Dow asks.

"Oh, of course, I know I'm taking a certain amount of risk. There is a risk factor involved in what I'm doing because I'm meeting a stranger," Kelly replies.

Before she was arrested last year on charges of promoting prostitution and money laundering, Kristin Davis ran a call girl agency in New York City. "We were grossing about $5 million a year," she says.

With a small fortune stashed in off-shore accounts, Davis says her company catered to everyone from princes to politicians and posted more than 300 ads a day on Craigslist.

In 2007, she claims she hired Julissa Brisman for high-end erotic massage - a job she says Brisman took seriously. Davis says Brisman took her safety seriously too. "She was smart, funny, full of life… and she had a lot of street smarts."

Davis thinks that should have been enough to save Brisman. But hard economic times and easy Internet access mean more people are selling erotic services online these days, without really checking out who's buying.

"It's easier, you know, for people who might, you know, be aspiring predators to find prey," Davis says. "They might not feel comfortable going out and actually doing the acts… and going through neighborhoods and tolling for their victims - they can do it all online… remotely from the privacy of their homes."

Just how easy is it to find a woman on Craigslist? To find out for ourselves, 48 Hours went online and started making some calls. In less than 30 minutes, three women agreed to meet us at a Manhattan hotel. Meet us for what you say? Well, they didn't say. But they all agreed to meet us at the hotel within a few hours.

Craigslist prostitution is such a problem in the Chicago area that Cook County Sheriff Thomas Dart says police stings can no longer keep up. So the county is suing Craigslist for creating a public nuisance. Dart wants the site to take its erotic ads down.

"They keep harping on the fact that it's a self-monitoring site and we're against crime," says Dart. "Wow. Fantastic.You're against crime. So am I. I'm doing something about it. You're doing nothing."

At the hotel suite in Manhattan, 48 Hours discovered that many of the women on Craigslist will gladly come to you. One of the first women we phoned, a 24- year-old European we'll call "Eve," showed up right on time. The room was rigged with hidden cameras; she agreed to talk to us.

"So would it be safe here to say that you're addicted to the money?" Dow asks.

"Yeah, definitely," Eve says. "Like, who, at 24 years old - when I was 22, just started - can make $1,800 a night. Nobody."

Eve claims she makes a bundle from her Craigslist sex ad, telling Dow, "I can stop anytime, but what am I going to do? I have to go work at Kmart or McDonalds and get $300 a week?"

Two more women showed up later; one was from Russia and then another, who left after Dow showed her a newspaper about the Craigslist killing.

Davis says the oldest profession on Earth will keep morphing to survive, much like Kelly, Eve, and the other woman we met on Craigslist.

"We have this illusion of living in this little bubble of safety," Davis says, "and that's just not the case. It could happen to anyone."