When you meet someone online, (tinder, plenty of fish, ok Cupid, etc.) and you want to make sure they're not a total psycho before you meet them. So you look them up on Facebook to see what they post, who they're friends with, what pictures you haven't seen, etc. Sometimes you are surprised by what you find...
I was kind of skeptical about Todd, so I ran a Facebook background check to see who he really is...
Asking everyone, looking for info via internet, becoming a straight stalker, nothing off limits, your insta, Twitter, Facebook, indeed, LinkedIn, google and providing all screen shot.
The act of checking your surroundings for any black people prior to making a potentially insulting racist joke and getting beaten. Usually the joker will state they are making the check out loud, much to the hilarity of those familiar with the term.
Johnny: So this black guy walks into a bar... Wait, gotta do a blackground check....