Craigslist dropped its "Adult Services" section last Friday, replacing it with a black banner that reads "Censored." The controversial — and as yet unexplained — change was just the latest salvo in an ongoing battle between the site and critics, including lawmakers, who have accused it of profiting from ads that promote prostitution, sex trafficking, and sex with children. Here are some of the key moments leading up to last week's dramatic development:

March 2007: California police raid the studio of a photographer and accuse him of taking semi-nude pictures of three girls — one 14, the others 17 — for prostitution ads in Craigslist's erotic services section. The case focuses increased attention on Craigslist, which has already been linked to prostitution stings in New York, Chicago, and Seattle.

July 2007: A 19-year-old Minnesota woman is charged with recruiting high school girls into a prostitution ring, and seeking clients with an ad for "party girls" posted on Craigslist.

November 2008: Responding to pressure from attorneys general led by Connecticut's Richard Blumenthal, Craigslist cracks down on its erotic-services ads. It requires a valid credit card number to create a post, among other restrictions.

April 2009: Philip Markoff, a 22-year-old medical student, is accused of killing Julia Brissman in a Boston hotel room. The two had met after Markoff responded to Brissman's massage-service advertisements on Craigslist. In the media firestorm that follows, Markoff is dubbed "the Craigslist Killer."

May 2009: Though it maintains that its ads don't promote violent behavior, Craigslist bows to pressure from lawmakers and shuts its "Erotic Services" section. It creates a new "Adult Services" section, vowing to manually review the posts. New posts to the section cost $10 each.

April 25, 2010:
The New York Times reports that Craigslist is set to make $36 million in 2010 from listings that advertise sex.

August 4: CNN reporter Amber Lyon confronts Craig Newmark, Craigslist's founder, over allegations that the site enables child-sex listings. Newmark is rendered speechless; he claims he was ambushed.

August 15: Philip Markoff, the accused "Craiglist Killer," commits suicide in a Boston prison cell, bringing attention back to his case.

August 24: Seventeen attorneys general send a joint letter demanding that Craigslist remove its Adult Services section, claiming that prostitution and child trafficking run rampant on the site.

September 3: Craigslist places a black-and-white "Censored" banner over its Adult Services section. That portion of the site is still available outside the United States, and erotic ads stateside are already migrating to the "Casual Encounters" section. Despite the apparent concession to Craiglist's critics, many observers think the change won't make much of a difference.

Sources: CNet, Boston Globe, New York Times, Jezebel