Mozilla, Facebook web tracking, ImageQuestEver wondered exactly how Facebook tracks you around the Web? The Mozilla Foundation has at least one answer: the buttons on websites that encourage users to find, like, or follow the organization on Facebook.

Mozilla, the Firefox web browser maker, says those buttons contain tracking code that tracks you on the Web – whether you click on the button or not.

“For example, when you are on a news site and reading an article, you often see Facebook Like and Share buttons,” the non-profit organization says in explaining a Firefox feature. “Our Facebook Container will block these buttons and all connections to Facebook’s servers so that Facebook isn’t able to track your visits to these sites. This blocking makes it much harder for Facebook to build shadow profiles of non-Facebook users.”

A shadow profile is one Facebook – or other social media outlets – builds of people who don’t provide their personal data to the outlet. Instead, Facebook and others use information from third parties – such as your friends who upload their contacts or sites you visit with the “Find Us on Facebook” buttons.

The buttons work with web browsers to add tracking pixels or cookies which transmit data back to Facebook, telling Facebook what you looked at around the Web. Thus, if you visit a clothing website and browse its “latest finds,” then visit Facebook, ads from the clothing company will show up in your feed (assuming the clothing company is a Facebook advertiser.)

If you don’t use the Firefox browser, clearing your browsing history is another way to limit the tracking. You would find this option in your Settings or Preferences.

You can test this by clearing your browsing history, closing and then reopening your browser, and going immediately to Facebook to see what ads show up in your feed.

Some browsers allow you to clear browsing history automatically when you close your browsers. If yours doesn’t have an automatic setting, you will have to clear your browsing history manually.

We should note that when organizations began adding Facebook connection buttons to their websites over a decade ago, most understood that choice as being about expanding their reach and audiences – and not so their fans and customers could be tracked on the Web.