Unintended Impact of Blocking Third-Party Cookies on Identity use cases

Browsers have introduced several security measures to protect user privacy regarding tracking user activity in the internet. Initially, browsers introduced same-site cookies to control the usage of third-party cookies. However, with recent updates, browsers are moving towards completely blocking third-party cookies. In this article, let’s see how blocking third party cookies can impact popular Identity use cases.

Why block third-party cookies?

First, let’s figure out how personalized and targeted ads works. Here is what happened when user clicks on an Ads

Image by clearcode.cc

Here is what’s happening in the image above:

1. The user visits a website and a first-party cookie (xzy890) is created by the website in its domain (example.com) and assigned to the user.
2. The user then clicks on the ad and is directed to the AdTech platform’s domain (ad.ads-r-us.com).
3. The AdTech platform creates a first-party cookie (klm456) under its domain (i.e. ads.ads-r-us.com) and assigns it to the user.
4. The AdTech platform then redirects the browser to the advertiser’s landing page (www.usedcarsite.com).