Companies use Facebook advertising system design to bypass labour laws
Research from ProPublica in December 2017 found that dozens of companies, including Verizon, Amazon, and Target are using Facebook to target job ads to exclude older workers. Excluding older workers is illegal under US law, but Facebook's system allows advertisers to specify precisely who should see their ads. Verizon, for example, specified that its effort to recruit applicants for a unit focused on financial planning and analysis would run on the Facebook feeds of users 25 to 36 years old who lived in or had recently visited Washington, DC and had demonstrated an interest in finance.
To any of the other billions of users on Facebook, these ads did not exist, leading experts to question whether the system violates the federal Age Discrimination in Employment Act of 1967, which prohibits bias against people aged 40 or older in hiring or employment. Facebook, which is becoming increasingly popular for employers, claims that age-based targeting for employment purposes is an "accepted industry practice". In a class action suit filed on behalf of the Communications Workers of America and all Facebook users over 40 who may have been denied the chance to learn about job openings, Facebook has argued that it is protected from liability for third-party content by Section 230 of the federal Communications Decency Act.
In March 2018 further ProPublica's research was added to a lawsuit.
https://www.propublica.org/article/facebook-ads-age-discrimination-targeting