"We believe that the majority of what has happened is that the 'erotic services' category has essentially been renamed and reconstituted," says Mark Plowden, communications director for McMaster.

Earlier this week, Craigslist forged an agreement with attorneys general in Illinois, Missouri and Connecticut to discontinue erotic services listings and create a new "adult" category for ads offering erotic massage, nude dancing and the like. The site also will charge $10 for an initial posting and will screen out ads for prostitution and ads with nudity or pornography.

That deal replaces one that Craigslist struck last year with 40 state attorneys general to require that erotic services advertisers provide credit card information and to charge $5 per ad, which would be donated to charity. Craigslist had come under increasing pressure in recent weeks to do more to police its site, largely due to the murder of masseuse Julissa Brisman. She was allegedly killed last month by a Boston University student who answered an ad she placed on Craigslist's "erotic services" section.

But it's not clear whether the new arrangement will result in fewer prostitution ads, or whether the ads will simply migrate to other, unmonitored areas of the site.

McMaster previously demanded that the site remove all prostitution ads by May 15 or face criminal prosecution. Craigslist has retained an attorney in South Carolina who has met with McMaster's office, but as of Thursday, nothing had been resolved, Plowden says. In addition, as of Thursday afternoon, some of the ads in the new monitored adult listings were still racy. For instance, one that ran in the Columbia, SC adult listings had an image that was arguably not-safe-for-work [Examples below as well].

Plowden says the site's managers can be charged under a state law that makes it a crime to facilitate prostitution. That same law allows state authorities to prosecute brothel owners.

But many cyberlawyers say Craigslist executives are in no danger of conviction because the Communications Decency Act provides that sites are immune from liability when users post material that violates state laws. That Communications Decency Act contains some exceptions -- such as for posts that violate copyright law -- but none of those exceptions would apply to prostitution ads.

"It's cut-and-dry," says Matt Zimmerman, a lawyer with the digital rights group Electronic Frontier Foundation, agrees. "There is no way that Craigslist is criminally liable for this."

Chris Wolf, an Internet lawyer with Hogan & Hartson, agrees that McMaster has "little to no chance of success" of prevailing in a criminal case.

Zimmerman adds that even the threat of criminal prosecution is "irresponsible." "If you want to change the law, go run for Congress, but don't threaten to send men with guns to drag someone off to prison when you know that's not possible," he says.

But because the law seems to clearly protect Craigslist, some are questioning why the site compromised at all. Zimmerman says the site is entitled to take down whatever categories it wishes, but that giving in to bullying tactics sends the wrong message. "I don't think it helps anyone, least of all them, to keep giving in to threats that have no legal basis," he says.