The Future of AdTech Lies in Privacy-Enhancing Technologies (PETs)

In the early days of programmatic advertising, ad targeting was limited to the context of the webpage and basic information pulled from the user-agent string — things like an IP address used to infer location.

Then, in the mid- to late-2000s, real-time bidding (RTB) arrived and changed the equation entirely. Companies began using web cookies to identify individual users across different websites, and those third-party cookies multiplied rapidly. Before long, they were being used to track millions of people across the internet, enabling behavioural ad targeting, audience measurement, campaign measurement, frequency capping, and attribution.

It didn't take long for the press to pick up on what was happening. News outlets started publishing stories about shadowy companies — names nobody recognized — quietly following users from site to site. Public awareness grew, and governments took note.

In 2016, the European Union released the General Data Protection Regulation (GDPR), giving EU citizens and residents meaningful rights over their personal data. It came into force on May 25, 2018, and reshaped how companies collect, store, and use personal information across the board.

But the most consequential privacy shifts were still ahead.

In 2017, Apple released the first version of Intelligent Tracking Prevention (ITP), a feature designed specifically to block cross-site identification — the core mechanism that third-party cookies depended on. Mozilla followed with a similar tracking prevention feature in Firefox. Then Google announced it would also eliminate support for third-party cookies in Chrome, a move expected to take effect in 2024.

By 2023, the cumulative impact of these changes had become impossible to ignore: somewhere between 30% and 40% of all web-browser traffic was unidentifiable due to the unavailability of third-party cookies. Apple compounded the pressure further by restricting access to its Identifier for Advertisers (IDFA) on iOS devices — another significant milestone in the broader push against user tracking.

Privacy-Enhancing Technologies as the Path Forward

The industry now finds itself navigating a fundamentally different operating environment. The tools that powered a generation of programmatic advertising are being dismantled, and the question facing every AdTech platform and advertiser is the same: what comes next?

The answer increasingly points toward privacy-enhancing technologies (PETs) — a class of technical solutions designed to enable data utility while minimizing privacy exposure. Rather than relying on individual user identifiers, PETs allow measurement, targeting, and attribution to function within privacy-preserving frameworks.

For companies working through this transition, the core areas worth understanding include:

• The current privacy landscape in programmatic advertising and how it got here.
• The practical alternatives to third-party cookies and mobile IDs.
• How businesses can adapt their data strategies to operate effectively in a privacy-first world.
• What privacy-enhancing technologies are, how they work technically, and where they fit in the AdTech stack.
• Why incorporating PETs into AdTech platforms and advertising operations is becoming a competitive and compliance necessity.

The Exchange Wire Industry Review 2023 report covers these questions in depth and is worth reading for anyone trying to get ahead of the ongoing deprecation curve.