"Facebook strictly prohibits pornography and adult content as part of its advertising guidelines, and it reviews ads running on the site to ensure they meet those guidelines," company spokesman Matt Hicks said in a statement. "In this case, Facebook immediately disabled three ads after a review revealed that they were displaying prohibited images."
It is unknown how many profiles displayed the ads, which advertised online chat with a photograph of a naked woman. Hicks said none of the ads was online for more than a few hours and estimated the potential viewership of the objectionable ads to be no more than 10,000 users.
Dozens of Facebook users posted comments about the ads, asking whether the ads were random or were targeted to specific people.
Hicks said the ads were not part of Facebook's recently launched Beacon targeted-advertising program, saying that the ads had been submitted through Facebook's self-service website, which uses a combination of technology and human review to catch inappropriate ads.
"In this case the image made it through tech filters and the human review caught it," Hicks said.