Social media platforms like Facebook are an ideal place for recruiters to look for candidates. But can powerful targeting tools allow companies to discriminate?

Almost four months ago, Lisa Dorahy was scrolling through Facebook when she saw a job advert pop up in her news feed.

She wasn’t really looking for a new job, and it was one of the rare times the mother-of-three had time to use social media. But the post advertising for a part-time assistant at a recruitment agency seemed perfect for her.

She followed the link to apply, had an interview three days later, and a job with New Zealand agency, Human Connections Group by the following week. Dorahy now realises the ad was specifically targeted to find her – or someone like her.

The ability to hyper-target candidates for specific jobs could also allow some recruiters to discriminate based on age, ethnicity, religion or gender

Facebook ads are not a new phenomenon – no doubt you’ve seen similar ads in your news feed. But you may have also seen job advertisements appear for roles and industries that are outside your regular line of work. This is likely the result of recruiters looking for someone with your specific skills, based off information that Facebook has learnt about you from your behaviour on the site.

As more recruiters begin to use the tool, some warn the ability to hyper-target candidates for specific jobs could also allow some recruiters to discriminate based on age, ethnicity, religion or gender.

When BBC Capital contacted Facebook it declined to comment on the practise of targeted recruitment on the platform.

It works like this: Facebook Ads is a service which allows businesses to pay to place advertisements on and around people’s Facebook feeds.

When placing an advert, the business can choose the exact type of person they want to see it, based on their age, sex, interests, race, religion and much more.

Facebook is not the only social media network to allow targeted advertising – any platform that collects data on its users can offer a similar service. For example, Google+ and Facebook-owned Instagram also offer hyper-targeted advertising, while LinkedIn allows recruiters to create targeted ads based on age or gender, but not on race or sexual preference.

A billion potential candidates

Founder of London-based digital marketing agency Link Humans Jorgen Sundberg estimates 10% of the UK’s almost 20,000 recruitment agencies are now using Facebook advertising.

“Facebook has the most data on anyone, arguably, out of all the tech companies,” he says.

A Facebook spokesman says the company could not share data on the number of recruiters using the tool, and declined to comment further.

Facebook has the most data on anyone, arguably, out of all the tech companies

With 1.13 billion daily active users, Facebook is a place where you can find candidates for all sorts of jobs, says founder of UK social media agency Social-Hire Tony Restell. “Venture capitalists are as likely to want to keep up with friends as truckers [are], so Facebook has a massive penetration across sectors.”

This huge variety of people on Facebook means advertisers need to be specific and accurate in their targeting. When they’re not, we end up seeing those job adverts that are laughably irrelevant to us.

But Facebook won’t stand for too much error, he says. It rewards advertisers with lower fees if the audience is interested in the advert, and punishes with higher fees it they’re not.

Bang for your buck

Human Connections Group founder and recruiter Emily Richards now uses Facebook to fill one in every three jobs.

The New Zealand-based recruiter says she  will spend NZ$20 ($14) to reach up to 10,000 people, depending on the demographic – which she says is a cost-effective option.

But the recruiter is also “acutely aware” of companies’ abilities to use the targeting function for discrimination.

“I think if put in the wrong hands it could be incredibly detrimental to gender equality, racial equality and all of that stuff we’ve worked so hard to get to a point that it doesn’t happen," Richards says.

Wanted: Single male. Vegans need not apply

For the purposes of testing just how targeted a job ad could be, BBC Capital attempted a test job advertisement on Facebook. First, we chose to target only males between the ages of 18 and 25, living in New York.

We then opted to ‘exclude’ all men who were parents or in a relationship. One could even exclude by race.

We then excluded all vegans, vegetarians and men who ‘like’ chocolate.

The resulting super-targeted job ad for a ‘Social Media Superstar’ was soon approved by Facebook and ready to go – heading out to 430,000 young, single, childless, meat-eating men.

Davida Perry, the managing partner of New York law firm Schwartz & Perry, says targeting specific job candidates through Facebook advertising could amount to a breach of several laws.

Targeted ads can be used by the dark side, but they can also be used for good

In the US, federal human rights laws forbid recruiting in a way that discriminates against people based on age, race, religion, gender, pregnancy, disability or sexual orientation.

In the UK, it’s illegal to discriminate when recruiting based on age, gender, pregnancy, sexuality, religion or marital status. Where you advertise can be discriminatory as well – for example, if you were to advertise a role only in men’s magazines.

So even though the targeted advertisements themselves might not appear discriminatory, the process of targeting them to some people and excluding others can be.

Although the process used to post some job ads could be illegal, these ‘failure to hire’ cases are “very, very hard to prove”, Perry says. “It’s hard enough to prove discrimination against someone in the workforce”.

But, she says, if the recruiter has publicised the targeting, it could open them up to legal repercussions like a fine or court order.

Facebook’s advertising policy states advertisements “must not use targeting options to discriminate against, harass, provoke, or disparage users”, and advertisers on Facebook are obliged to make sure their ads comply with the law.

Facebook declined to comment on the practise of targeted recruitment on the platform.

A force for good

Despite the risk, online recruitment specialists urge people not to think the worst.

Link Humans’ Sundberg uses the analogy of ‘the force’ in Star Wars: targeted ads can be used by the dark side, but they can also be used for good.

“There’s always rogue players out there, but on the whole it’s all legit. If you’re a recruiter or an agency recruiter everyone is screaming out for diversity, so I don’t see why you would use it to discriminate.”

To comment on this story or anything else you have seen on BBC Capital, head over to our Facebook page or message us on Twitter.