Ross Benes:

Apple is cracking down on ad tracking through Safari, and the first publishers to feel the pain are those who rely heavily on programmatic advertising.
 
 Programmatic publishers’ ad rates have taken a hit since Apple updated its Safari browser last month to prevent third parties from tracking users for more than 24 hours after a user visited a website. Although Apple’s move hurts publishers reliant on third-party data that advertisers depend on to target niche audiences at scale, publishers that sell their inventory directly say they aren’t affected by the Safari update.