The Hidden Cookies in Some Cookieless Solutions

The demise of third-party cookies has been a major challenge for the programmatic advertising industry, which relies on user tracking and targeting across domains. While some browsers, like Safari and Firefox, have already blocked third-party cookies, Google Chrome plans to do the same by the end of 2024. This has prompted many brands and ad tech providers to look for alternative solutions that can offer similar functionality without violating user privacy.

However, not all cookieless solutions are truly cookieless. Some of them use a technique called ID bridging, which essentially uses third-party cookies from Chrome to identify users and then matches them with other identifiers (such as IP addresses) in cookieless environments like Safari. This way, they can still access the user’s browsing history and preferences, even though they are on a different browser.

What is ID bridging, and why is it misleading?

ID bridging is a technique that some alternative ID solutions use to target and measure audiences across cookieless environments. For example, a buyer might use an alternative ID solution to target users on Safari, where third-party cookies are blocked. But instead of relying on a consented first-party identifier, the solution uses a third-party cookie from Chrome to identify the user and then uses a bridge (such as an IP address) to find the same user on Safari. This way, the buyer can access the user’s browsing history and preferences from Chrome, even though they are on a different browser.

This technique is misleading for several reasons. First, it violates the user’s privacy and consent, as they may not be aware that their data from Chrome is being used to target them on Safari. Second, it creates a false impression of the effectiveness of the alternative ID solution, as it relies on third-party cookies that will soon be deprecated. Third, it does not prepare the buyer or the publisher for a truly successful future, as it will not work once Chrome blocks third-party cookies.

How do you detect and avoid ID bridging?

ID bridging is not a transparent or ethical practice, and it should be avoided by buyers and publishers who want to comply with privacy regulations and user expectations. However, detecting ID bridging can be tricky, as some alternative ID solutions may not disclose how they operate or what data they use.

One way to detect ID bridging is to look at the match rate of the alternative ID solution in cookieless environments. If the match rate is unusually high (above 50%), it may indicate that the solution is using ID bridging. Another way is to ask the alternative ID provider to explain how they generate and match their identifiers and what data sources they use. If they are vague or evasive, it may be a red flag.

To avoid ID bridging, buyers and publishers should look for alternative ID solutions that are truly cookieless and consent-based. These solutions should use first-party data, such as email addresses or login IDs, to create and match identifiers across domains and devices. They should also respect the user’s choice and opt-out preferences and provide transparency and control over how their data is used.

What are the benefits of truly cookie-less solutions?

Truly cookieless solutions are not only more privacy-friendly but also more future-proof and effective. They offer several benefits for buyers and publishers, such as:

• Higher accuracy and quality: First-party data is more reliable and relevant than third-party data, as it reflects the user’s actual behavior and interests. It also reduces the risk of data leakage, fraud, and duplication.
• Better user experience and trust: Users are more likely to share their data and consent to advertising if they trust the brand and the platform. They also appreciate ads that are personalized and respectful of their privacy.
• More innovation and collaboration: Truly cookieless solutions require more creativity and cooperation among the industry players, as they need to find new ways to measure and optimize their campaigns without relying on third-party cookies. This can lead to more innovation and value creation for the ecosystem.