The debacle with Cambridge Analytica has uncovered some nasty behaviour by Facebook. For many, this doesn’t come as a surprise, although the extend of it perhaps does.
It is good to understand that Facebook’s users and its customers are not the same groups. Regular folk who like to share pictures with their families and friends and handle events through Facebook are not Facebook’s customers. Advertisers are. Facebook makes no money directly from their users (“it is free, and it will stay free”, they say), the money comes from advertising.
Trackers are what makes online advertising work.
It is the users’ data that ultimately generates the advertising revenue. It makes sense for Facebook to track people, not just their users but everyone, as they navigate the internet. One of the way they do this is by using a “pixel”: a tiny image consisting of a single pixel that is placed — together with a link to Facebook — on websites. Such a pixel is called a “tracker”, and it isn’t unique to Facebook. Generally speaking, trackers are what makes online advertising work, because they follow your every (online) move.
If you feel uncomfortable being tracked by Facebook, especially if you’re not an actual user, you might want to make sure that they can’t. Luckily, this is quite easy to achieve by installing Privacy Badger , a project of the Electronic Frontier Foundation, or EFF.
Privacy Badger examines websites to determine whether you are being tracked. If you install it without changing the settings, it will determine by itself whether you’re tracked: if a single tracker is found on three different sites, it will be disabled.
You already know that you want to block the Facebook pixel.
since you already know that you want to block the Facebook pixel, you
can click on the Privacy Badger icon in the browser toolbar and change
the slider for the domain
connect.facebook.net to ‘Disabled’:
The Dutch organisation “Bits of Freedom”  has created a web page where you can check whether Privacy Badger blocks the Facebook pixel.  If it’s the first time you visit the site after installing Privacy Badger, it may still be allowed. You can manually disable the pixel by moving the slider to the far left. Otherwise, it will be disabled automatically when you visit the third site that has the pixel.
Naturally, Privacy Badger works for many different trackers, not just for the Facebook pixel. But because it keeps track (ahem) of the trackers’ usage, you don’t have to configure it yourself. It’s interesting, though, to know which trackers are found on various sites. You can see this by clicking the icon in the toolbar.
Finally, some trackers actually help a site’s functionality, e.g., by serving third-party images or style sheets. Privacy Badger will allow those connections, while screening out tracking cookies and referrers.
Privacy Badger is available for Google Chrome, Firefox, and Opera. Microsoft Edge is not yet supported, and Safari isn’t even mentioned.
 Privacy Badger: https://www.eff.org/privacybadger
 Bits of Freedom: https://www.bof.nl/
 Evelyn Austin’s Pixel test: https://eaustin.nl/pixeltest/
 Privacy Badger’s logo source: https://www.eff.org/privacybadger (Shared unchanged under the Creative Commons Attribution License, CC BY 3.0 US)