"In our view, the company should take immediate action to end the misery for the women and children who may be exploited and victimized by these ads," last week's letter stated. "Because Craigslist cannot, or will not, adequately screen these ads, it should stop accepting them altogether and shut down the Adult Services section."
On Aug. 18, six days before the letter was sent, Buckmaster said on Craigslist's blog: "Craigslist is committed to being socially responsible, and when it comes to adult services ads, that includes aggressively combating violent crime and human rights violations, including human trafficking and the exploitation of minors. We are working intensively as I write this with experts and thought leaders at leading non-profits and among law enforcement on further substantive measures we can take."
The site was embroiled in a related controversy in 2009 when Philip Markoff, a Boston University medical student, was charged with the murder of Julissa Brisman, whom he allegedly met through Craigslist's Erotic Services section.
In August Markoff was found dead from an apparent suicide in his cell in Boston's Nashua Street Jail.
The Erotic Services controversy was heightened earlier this month when two young women identifying themselves as former child prostitutes going by "MC and AK" took out an advertisement in the Washington Post and claimed to have been sold via Craigslist.
Buckmaster responded by asking for further details on the arrest of their exploiters and reiterating the site's stance on the subject.
"We work with law enforcement to bring to justice any criminals foolish enough to incriminate themselves by misusing our site, and want to make sure everything possible has been done in your cases," Buckmaster wrote. "Even politicians looking to advance their careers by publicly criticizing us grudgingly admit (when pressed) that we have made giant strides in fighting trafficking and child exploitation."