There is reasonable cause to believe seven companies used Facebook advertising to discriminate against women and older workers in the job market, according to a landmark ruling by the federal Equal Employment Opportunity Commission (EEOC) made public this September.

Businesses can legally advertise products and services by targeting groups whose attention could help the company’s bottom line. But federal law defines limited situations where targeted advertising can break the law. These rules are designed to end discriminatory advertising (an open practice in the past) in jobs, housing, real estate, banking and other opportunities.

Investigative journalism raises the alarm

A major value of online advertising lies in its power to target very specific audiences, showing certain messages only to the kinds of people the advertiser most wants a specific message to reach.

But beginning two years ago, organizations with investigative teams began reporting that a wide variety of companies were discriminating against older workers and women by preventing people in these groups from seeing job postings on Facebook.

In one simple research approach, Facebook’s “Why am I seeing this ad?” feature told users that only people in a certain age range, for example, could see the employment ad. Visual elements of such ads depicting prospective future employees often reinforced the discriminatory targeting.

A flood of complaints and lawsuits yield a major ruling

The EEOC’s ruling against the companies is the first such ruling against this kind of targeted advertising, constituting a major challenge to Facebook as well as a much broader business sector. The Commission’s ruling is part of its settlements with companies, which include agreements to change behavior.

Class-action and other lawsuits filed by the American Civil Liberties Union, the Communications Workers of America and many other groups and individuals are still pending, and this finding of reasonable cause by the EEOC is expected to play a significant role in what comes next.