In an interview with ABC Nightline's Martin Bashir, Newmark also said he disagreed that the site facilitates prostitution. "I wouldn't put it that way; no, I disagree," he responded when Bashir confronted him with ads that appear to be for prostitution and asked whether the site facilitates such activity.

Earlier this month, Boston University student Philip Markoff allegedly murdered masseuse Julissa Brisman, who had placed a Craigslist ad offering erotic massage.

Her death has resulted in renewed scrutiny of Craigslist's "erotic services" listings. Last week, Connecticut Attorney General Richard Blumenthal, for one, demanded that the site stop accepting prostitution ads.

Craigslist also faces a federal lawsuit in Illinois, filed by Chicago sheriff Thomas Dart. In that case, Dart alleges that the site's erotic services ads facilitate prostitution. Dart argued that the term "erotic services" self-evidently refers to prostitution. But Craigslist says in an FAQ that the section is supposed to house ads for services like "sensual massage, adult web cams, phone sex, erotic dancing, adult websites, nude housecleaning, etc."

Internet law experts say that legal action against Craigslist isn't likely to get very far because Section 230 of the Communications Decency Act states that Web sites are immune from liability when users of the site violate state law.

Separately, last November Craigslist forged a deal with 40 state attorneys general to charge a small amount for erotic services ads. The site now also requires that advertisers provide credit card information, and donates revenue from those ads to charity.

This news story is important. I recommend that everyone read it.