Third-Party Cookies

A third-party cookie is a piece of data that is...

A third-party cookie is a piece of data that is placed on a user's hard disk by a website domain other than the one a user is visiting. They can also be referred to as trackers because they track users across different domains.

Why would I need this?


Third-party cookies are used by advertisers and social networks to monitor user activity online and for behavioral targeting. This is useful for advertisers because specific user data can enhance the campaign's success by marketing the user relevant products. 

User profiles can be made from this data to inform how information will be presented to the user, whether it be an advertisement pop-up or a social media feed.

How does it work?


Third-party cookies work by embedding third-party JavaScript code from one website into another. HTTP, the protocol used for web browsing, means stateless information is not saved in between browsing sessions. But cookies remember stateful information (information that is remembered in between sessions) in the stateless HTTP environment.

When a user performs any action on the browser or site, the cookie attributes (whether it is first, second or third party) determine if and when cookies will be sent along with the response.

Real world examples


Devilled data: Attention Seekers, episode 9

The cookiepocalypse is nigh (again)!

68% of consumers uncomfortable with their data being used for ads, but two-thirds are still likely to visit a site after being targeted