Safari 3rd Party Cookies

The future of tracking in Safari is "aggregated" rather than "individualized." Advertisers will know that 5,000 people bought a product after seeing an ad, but they won't know who those people are individually.

While Google Chrome has delayed the "cookiepocalypse" (the phase-out of cookies) multiple times, Safari has effectively already enacted it. For developers, this means assuming third-party cookies do not work in Safari is the safest default setting. safari 3rd party cookies