Facebook Inc. is adding more human reviewers to oversee its advertising system after a report showed that people could target ads at users interested in anti-Semitic and other hateful topics.
The problem stems from how Facebook's ad system automatically mines information from user profiles to create specific topics that advertisers can pay to target.
In a report last week, news outlet ProPublica showed that the system could enable someone to show ads to Facebook users whose profiles included terms like "Jew hater" or "How to burn jews."
The number of users for each anti-Semitic term was tiny, and it isn't clear if any advertiser actually used the hateful terms. Still, the episode has again spotlighted Facebook's failure to anticipate and detect how its platform can be manipulated for ill purposes.
"We never intended or anticipated this functionality being used this way -- and that is on us," Chief Operating Officer Sheryl Sandberg said in a Facebook post Wednesday. "And we did not find it ourselves -- and that is also on us."
Ms. Sandberg said Facebook would conduct more manual reviews of new ad targeting options that automatically appear in its system. It restored about 5,000 of the most common targeting terms used by advertisers, such as "nurse", "teacher" or "dentistry," after conducting a manual review of those topics.
Facebook has faced similar backlash for allowing violent videos to broadcast over its live-streaming tool and misinformation to proliferate across its network. This month, it disclosed that Russian actors bought more than 5,000 ads with divisive political messages during the presidential campaign, despite previously saying it had no evidence of this activity.
Facebook has spent years developing its ability to pinpoint consumers based on their interests, helping the company become a digital-advertising platform of enormous scale and amass a market value of $500 billion.
ProPublica's inquiry prompted Facebook to remove the anti-Semitic categories, but the company later disabled some of its targeting tools when that didn't fix the problem, Ms. Sandberg said.
The "Jew hater" topics reached 2,274 people, according to ProPublica. Advertisers could reach five people who said they worked for "Jew Killing Weekly Magazine," The Wall Street Journal found.
"The fact that hateful terms were even offered as options was totally inappropriate and a fail on our part," Ms. Sandberg said.
Ms. Sandberg didn't say how many human reviewers would be added to oversee the ad system. A Facebook spokeswoman wouldn't comment.
Write to Deepa Seetharaman at Deepa.Seetharaman@wsj.com
(END) Dow Jones Newswires
September 20, 2017 19:09 ET (23:09 GMT)