Between them, they’re responsible for the worst ills of the World Wide Web.Ģ019 is the year we apparently reached the breaking point. It’s hard to believe that we ever allowed third-party cookies and scripts in the first place. The default stuff is the big deal, because all browsers offer some way to block third-party cookies. Edge and Firefox plan to match the change. Slightly different in that the cookies will set themselves as first-party only by default. Chrome: Blocking by default is coming (February 4th, 2020).The “balanced” level in the middle still allows stuff like third party auth (June 27, 2019). Edge: You can enable tracking prevention and pick a level.Firefox: Blocks known-trackers by default (September 3, 2019).Safari: “Intelligent Tracking Prevention” is more complicated, but it does block third-party cookies by default (February 21, 2019).Eric goes on to explain the browser landscape: As you browse more and more sites that contain a tracking pixel from the same provider, that provider can build up a very complete profile of the sites you like to visit, and use that information to target ads to you, sell the data to a data aggregation company, etc.īut times are a changin’. If you later visit B., which also contains a tracking pixel from ad., the tracking pixel’s cookie set on your visit to A. is sent to ad., and now that tracker knows that you’ve visited both sites. The tracking pixel’s cookie is called a third party cookie because it was set by a domain unrelated to the page itself. That request to another site for the image (say, ad.) also can set a cookie.

A common tactic in online advertising is to render a “tracking pixel” image (well named, right?) that is used to track advertising impressions.

But might also load an image from some other site. For example, if I log into, I’ll get a cookie from that handles my authentication. Third-party cookies are set on your computer from domains other than the one that you’re actually on right now.

Brave third party cookies