Safari has finally blocked all third-party cookies by default. This means advertiser or web pages are not more able to follow you through the Internet using any tracking technology.
Apple engineer John Wilander tweeted a tweet stating that “The long wait is over and the latest update to Safari’s Intelligent Tracking Prevention is here..” linking to a blog post with full information.
Google is on track to introduce full third-party cookie blocking by default as well, but isnt expected to do so until some point in 2022.
Wilander also thanked to Google Chrome for helping him developing and progression Intelligent Tracking Prevention (ITP). He goes on to further details for some other more elements of upgrading ITP.