Apple's Safari Blocklist Brings Publishers Back to IAB Tech Lab's Trusted Server

The blocklist became one of the main topics at the recent Advertising Week New York — mostly behind closed doors, as companies are wary of publicly commenting on Apple's actions.

What is Trusted Server and why it came back into focus

The blocks have brought publishers back to a solution they had long filed away in the "someday" folder: launching their own advertising infrastructure via Trusted Server, a framework from IAB Tech Lab.

How it works:

• Today, the advertising process runs through the reader's device: the phone or tablet itself reaches out to dozens of ad-tech companies.
• Trusted Server takes the device out of this loop and moves the advertising process to servers controlled by the publisher itself.
• Apple doesn't see these requests, which means it can't block them based on its list.

The logic is frankly asymmetrical: Apple can't stop what it can't see. The company's only remaining option would be to block the news site itself. But that would break it for all Safari users, which Apple obviously won't do.

What's next

The threat publishers once dismissed as hypothetical now has a deadline — and Apple itself set it. The question is no longer whether the company blocks trackers in Safari, but how far the list will go.

So far, the blocks have targeted the biggest players in the ad-tech market. But if Apple expands the list to the mid-tier segment, the entire publisher–traffic-buyer pairing will take the hit, and falling bids will become systemic.

Trusted Server previously sparked debates in the industry — arguments for and against the framework were discussed back when IAB Tech Lab first presented it. However, the Safari situation has sharply increased the technology's practical value: what yesterday was a subject of discussion now looks like insurance against Apple's unilateral decisions.

For publishers, the calculus comes down to a simple choice: depend on ad-tech partners that Apple can switch off with a single update, or move advertising operations to their own servers and out of the browser's line of sight. Judging by the growing interest in Trusted Server, more and more publishers are leaning toward the latter.