Although many may think third-party cookies are simply an upgraded version of first-party cookies, it is not necessarily the case. The main differences between first and third-party cookies are:

• Setting the cookie: A first-party cookie is set by your web server or any JavaScript you have loaded onto this website. Third-party cookies can come from an advertising vendor, as well as code that has been put on our site directly and henceforth recognized with these technologies called "third parties."
• Cookie availability: Cookies are a way to remember what you have chosen on one website so that they can be restored when visiting another site. First-party cookies will only show up if the domain which created them is also being used as an entry point, while third-party ones should work cross-domain without any issues whatsoever!
• Browser support/blocking: The user can delete third-party cookies from their browser, but many browsers block this action by default. First-party cookie support is universal across all browsers and deleted ones will not be stored on your computer unless you enable them first!

There are so many differences that third-party cookies are now being phased out from many web browsers. This is a big change for advertisers and knowing what to expect ahead of time can help you use this change to your advantage.