Who we are on social media is who we are in life -- or who'd like to be -- and Facebook has a way of sorting us by our politics, even if we don't post about it.
Some of our political leanings are more obvious than others. Chances are if you like eating Ben & Jerry's in an electric car while listening to Peter, Paul, and Mary, then you're an older Bernie Sanders supporter.
Here's how you find out how Facebook labels you. Log on to the website on your desktop and go to facebook.com/ads/preferences.
Scroll down and you'll see an "Interests" page. Click on the tab labeled "Lifestyles and Culture" and click on "U.S. Politics,” or if that doesn't appear, then scroll down and click on the "See More" button.
When you see a box that says "U.S. Politics," hover your mouse over it and you'll see the political preference Facebook labels you under.
Campaigns use this information to advertise directly to users, so it's not a coincidence that you're seeing Donald Trump ads if you like a page featuring Ronald Reagan or George W. Bush.
(h/t The New York Times)