
How Social Marketers Use Data on Facebook
By: Erica Shubin
CommCreative’s Senior Social Media Strategist gives you a peek under the hood of Facebook advertising.
Hear this from someone who has built and managed Facebook-targeted audiences for more than eight years: When it comes to how much your marketer knows about you, your wants and desires as they play out on Facebook, it’s not as drastic as you may think. But when it comes to what Facebook knows about you, that’s a different story.
It’s a long-running, not-so-funny joke between, well, everyone who uses Facebook, that Facebook knows us intimately because they listen to everything we say and put the things we want in front of us through ads.
And, while some have investigated (see: Reply All episode 109: "Is Facebook Spying on You?") and found no hard evidence that Facebook is the new Big Brother, to the consumer, the coincidental evidence amassed can seem damning.

Personally, I haven’t experienced Facebook offering me ads too-connected-to-be-coincidence, but I have noticed the congruence between the very adorable Australian pit bull brothers I follow on Instagram (a Facebook-owned company) and the sudden appearance of Tooth & Honey brand dog clothing for “big-boned dogs” as sponsored ads in my Instagram feed: an ad serve that occurred without a visit to their website.
But when it comes to how marketers use your amassed personal data to reach the right people on the platform, Facebook is still pretty tight-lipped about it all, with us just as much as they are with you.
If we obtain data, like email addresses, through a source outside of Facebook, we can use your personal information to add you as one of the thousands of people comprised of the audience we are trying to get our ads in front of. This is known as building a custom audience, and it includes data related to:
- Website visits and the actions you take on a particular website
- Direct Facebook page engagement
- Email lists
- Down-funnel actions you take from seeing a Facebook ad, like submitting a form
Outside of custom audiences, Facebook relies on a set of prescribed interests to build what they refer to as saved audiences. The interests available are vast, but they have limits and may not be as telling as you think.
Having a presence on Facebook doesn’t necessarily mean your advertiser can choose that business as a targeted interest. The same goes for the interests you list on your profile. That’s where custom audiences fill in targeting gaps that interests alone can’t achieve.
In terms of more personal demographic data, like whether you own a home or your shopping behavior, Facebook dropped many capabilities over a year ago when the Facebook data privacy alarm bells first sounded due to their breach of data protection regulations through partnership with third-party data platforms.
In a similar vein to the broadness of the interests we can select for non-custom audiences, there is also little we can report back on you. I can break down impressions and clicks by gender, age range, regional location and device, but I can’t tell who among those engaging with an ad is doing so because they work in health care, for instance. I can’t even pinpoint to a city.
But where is all your data coming from?
Almost all websites have some relationship with Facebook advertising that requires the placement of a Facebook pixel on their website. That pixel gives Facebook access to your web behavior, and while the pixel is specific to a particular ad account, Facebook has oversight into every account to strengthen audiences.
The iOS 14 updates, which you can learn more about here, certainly aren’t good for Facebook. If Facebook can’t track a user’s journey as they wander around the internet from their iPhone, they’ll lose, among other things, important mapping information to build out intricate personas that likely comprise a lot of the personalization that goes into interest-based targeting we don’t have complete visibility into. Not to mention what advertisers will lose in retargeting capabilities on the custom side.
And that is one essential way Facebook knows what you like!
Another is through partnerships. Even without the reliance on third-party data providers, Facebook is still working with many companies to “get to know you better.” (Isn’t that a phrase you never want to hear from your social media platform?) Facebook is capable of collecting “offline” data through purchases you made in the real world and funneling you into the “shops at so-and-so store” camp for a specific store to target you even if you’ve never engaged with the company in your online behavior.1
Last, Facebook harnesses all of the data available within their platform or those they own to figure out what you like. That includes not only pages you’re following but also pages you’ve engaged with. Did you like a post from a politician running for office and suddenly noticed Facebook knows where your political affiliations lie when it comes to served political ads? That’s no coincidence.
This is some of what Facebook thinks I might want to see online, determined by my profile information, pixel captures and platform usage.
So, Facebook does know a lot about you today without breaking the law. Perhaps more than you’d like. But I hope it gives you a little comfort to know that, while Facebook may know your favorite color based on the sweaters you like on Instagram and preferred brand of bread from your latest grocery shop, your friendly neighborhood marketer very much does not. She’s just telling Facebook to find people who like sweaters and bread and hoping the pool of people is just right to net some solid results.