How directly can Facebook target you?

NEW YORK — If you want to tailor a Facebook ad to a single user out of its universe of 2.2 billion, you could.

Targeting ads, it turns out, is almost infinitely customizable. The ads you might see can be tailored to you down to the most granular details — not just where you live and what websites you visited recently, but whether you’ve gotten engaged in the past six months, are interested in organic food or share characteristics with people who have recently bought a BMW, even if you’ve never expressed interest in doing so yourself.

Facebook made $40 billion in advertising revenue last year, second only to Google when it comes to its share of the global digital advertising market.

Here are some ways advertisers can target you through Facebook:

By now you’ve probably gathered that Facebook uses things like your interests, age and other demographic and geographic information to help advertisers reach you.

Then there’s the stuff your friends do and like — the idea being that it’s a good indicator for what you might do and like.

Facebook and advertisers can also infer stuff about you based on things you share willingly. For example, Facebook categorizes users into an “ethnic affinity” based on what it thinks might be their ethnicity or ethnic influence.

It might guess this through TV shows or music you’ve liked. Often, Facebook is wrong — and while it’s possible to remove it, you can’t change it. There is also no “ethnic affinity” option for whites.

This became a problem for Facebook in 2016, when ProPublica found that it let advertisers exclude specific ethnic groups from seeing