For the investigation, ProPublica paid $30 to verify that users with such anti-Semitic phrases in their profiles saw the posts it promoted.
ProPublica, an investigative news organization, reported on Thursday that the social network's self-service ad-buying system allowed people to direct advertisements to almost 2,300 users interested in several explicitly antisemitic subjects, including a category labeled "History of "why Jews ruin the world".
While ProPublica put a deliberately bland advertisement out to these people (it was approved by Facebook within 15 minutes), the risk is that others could use the social network's unprecedented ability to target people by their interests to spread propaganda or organise far right rallies. All of these categories were created by users - rather than Facebook or advertisers - as they self-reported their education and employment history with offensive terms and labels.
This is not the first time Facebook's ad system has come under scrutiny.
Facebook removed the ad categories immediately after being contacted by ProPublica, stating that it will attempt to fix the problem and scrutinize more closely what ad categories were available. Since the "Jew hater" category was a small group - 2,274 users - Facebook automatically suggested adding related categories like "Nazi Party" and "German Schutzstaffel" (the Nazi SS) to reach more people. "In this case, we've removed the associated targeting fields in question", he told ProPublica. Facebook said it has built new "guardrails" into product-and-review processes to prevent something similar from occurring in the future. Last week, Facebook admitted that "inauthentic" accounts, thought to be operated out of Russian Federation, had placed $100,000 worth of ads between June 2015 and May 2017.
Last year, ProPublica was able to block an ad that we bought in Facebook's housing categories from being shown to African-Americans, Hispanics and Asian-Americans.
The Google-owned company and social media giants such as Facebook and Twitter have been warned by the Government they must do more to moderate their platforms for hateful content.
Not very thumbs up: Anti-Semitic ad targeting found possible on Facebook.
The ProPublica researchers found the anti-Jewish categories while conducting a larger investigation into the way Facebook targets adverts at users. The statement pledges to improve filtering and responses to discrimination, hate speech, threats, and other such uses of the platform.
"Given that the number of people in these segments was incredibly low, an extremely small number of people were targeted in these campaigns", the company said.
"Keeping our community safe is critical to our mission", Facebook said in a statement. In the wake of the violent protests in Charlottesville by right-wing groups that included self-described Nazis, Facebook and other tech companies vowed to strengthen their monitoring of hate speech.
Advertisers who notice any offensive or inappropriate targeting fields are asked to report them.