In response to the Facebook data harvesting scandal, Mozilla has launched an extension for its Firefox Browser which helps you segregate your web activity from Facebook's prying eyes by isolating your identity into a separate "container." This makes it far more difficult for Facebook to track your activity on other websites using third-party cookies.
You can get the extension here.
Upon installation, the extension deletes your Facebook cookies and logs you out of Facebook. The next time you visit the social media giant, it will open in a special blue browser "container" tab - which you can use to safely log in to Facebook and use it like you normally would. If you then click on a link that takes you outside of Facebook, it will load outside of the container.
Should you click on any Facebook Share buttons on other browser tabs it will load them within the Facebook container. You should know that when you’re using these buttons information will be sent to Facebook about the website that you shared from.
If you use your Facebook credentials to create an account or log in using your Facebook credentials, it may not work properly and you may not be able to login. Also, because you’re logged into Facebook in the container tab, embedded Facebook comments and Like buttons in tabs outside the Facebook container tab will not work. This prevents Facebook from associating information about your activity on websites outside of Facebook to your Facebook identity. So it may look different than what you are used to seeing. -Mozilla.org
Think of it as a condom for Facebook.
Mozilla notes that it "does not collect data from your use of the Facebook Container extension," adding "We only know the number of times the extension is installed or removed."
One Reddit user asks "why not just make every tab an isolated container? "There should be NO REASON for one tab to know or read what another tab (aka cookies) are doing from another domain," states /u/Pro2U
Lo and behold, the Mozilla programmer who created the extension popped into the thread and answered the question:
What you describe is actually possible in Firefox. It's called "First Party Isolation": https://wiki.mozilla.org/Security/FirstPartyIsolation
When we studied various privacy protections, FPI had a higher amount of website breakage reported by users: https://blog.mozilla.org/data/2018/01/26/improving-privacy-without-breaking-the-web/ -/u/groovecoder
So there you have it - if you don't want Facebook harvesting most of your data and tracking you around the web, strap on the Firefox extension and go to town.