When Craigslist withdrew from the adult services business last year, some wondered whether the prostitution business would be driven to less obvious and, perhaps, more dangerous places.

However, a Columbia University professor is suggesting that the business might have gravitated to somewhere even more obvious: Facebook.

Sociology professor Sudhir Venkatesh published the results of his work among New York prostitutes on Wired. And it makes for a stimulating insight into how technology is influencing the prostitution business.

Technology seems to have made men's behavior suddenly sophisticated.

"No self-respecting cosmopolitan man looking for an evening of companionship is going to lean out his car window and call out to a woman at a traffic light," Venkatesh said.

Is Facebook a new, discreet red light district

Instead, Venkatesh estimates that 83 percent of prostitutes have a Facebook page. Moreover, he believes that by the end of 2011, Facebook "will be the leading online recruitment space." Indeed, he says, even before Craigslist beat its retreat, Facebook was becoming a happy home for many prostitutes.

With more discreet and personal access offered through cell phones, the web and Facebook in particular, he believes that prostitutes "can control their image, set their prices, and sidestep some of the pimps, madams, and other intermediaries who once took a share of the revenue."

Even in 2008, he estimates that 25 percent of prostitutes' regular clients came through Facebook (compared with only 3 percent through Craigslist).

Perhaps it seems obvious. If every other form of relationship is made through Facebook, why wouldn't the more professional kind

While the professor doesn't go into details about how connections are made with prostitutes on Facebook, some might assume that they might follow the same pattern as any other friending. But perhaps it might be more complicated, with a little more inside code employed to keep things discreet.

Still, if everything is becoming more personalized, as well as more social, why should anyone be surprised that Facebook might be the obvious place for a chance encounter or an adult service

One can only imagine that prostitutes are, unlike some, very well versed in the Facebook privacy settings.