How to block third party cookies

Nearly all tracking and profiling of people on the Web starts with cookies planted in browsers by websites—and almost all of those planting the cookies are third parties rather than sites themselves.

Cookies planted by sites for their own purposes—and yours—are generally harmless and beneficial. For example, it’s a cookie that helps a site remember that you’ve been there before, or that have an account with a shopping cart.

Cookies planted for “marketing” purposes are mostly meant to track you about the Web, ostensibly to give you “relevant” or “interest-based” advertising.

Lou Montouli, who invented the cookie in 1994, said that “the goal was to create a session identifier and general ‘memory’ mechanism for websites that didn’t allow for cross-site tracking.” But cross-site tracking is what countless cookies do when you visit most of the world’s ad-supported websites. Up to hundreds of them may be loaded and re-loaded in your browser when you’re looking at a Web page.

The “adtech ecosystem” that generates and processes these third parties is vast, complex and thick with fraud, malware and unaccountability—all motivated by rationalized surveillance of human beings. As security expert  T.Rob Wyatt puts it In Online advertising is the new digital cancer, by not blocking third party cookies (and the ads they ride in on) you are “self-selecting into the cybercriminal’s target pool.”

The EU’s General Data Protection Regulation (GDPR) is meant to protect people from this kind of surveillance; but many of the perpetrators will still find loopholes, and you’ll still be tracked. The good news is that you can plug those loopholes easily by blocking third party cookies. Here’s where to go in the preferences panels of five browsers:

Brave (in “Shields”)

Chrome (in “Advanced” —> “Privacy and Security” —> “Content Settings” —> “Cookies”)

Firefox (“Privacy and Security” —> “Browser Privacy” —> “History”)

Opera (in “Advanced”)

Safari (in “Privacy”)

Microsoft Edge on Windows 10

  1. Open Settings under the 3-dotted ‘More’ link
  2. Scroll down and click on View Advanced Settings
  3. Scroll down to the setting for Cookies
  4. From the 3 options, select the one for blocking third party cookies.