UNDERCOVERLABIn 2024 two things happen at once. Google starts blocking third-party cookies for a share of Chrome users, and the EU’s Digital Markets Act (DMA) forces a "reject all" button onto cookie banners. If you advertise with Google, this hits your bottom line. Here is what changes and what you need to do.
What happens in 2024
Two changes in parallel. The first, technical: Chrome stops reading third-party cookies for a percentage of users. The second, legal: the DMA requires cookie banners to let people reject tracking in a single click, as easily as accepting it.
The practical consequence lands on Google. When the DMA takes effect, anyone who wants to keep using Google’s advertising products has to upgrade Consent Mode to version 2. The deadline is April 2024. From there, without V2 you lose the ability to measure and to advertise.
The same shift raises the value of your own data. First-party data, what your site collects with consent, and zero-party data, what the user hands you directly. When third-party cookies disappear, that data becomes your asset, not the platform’s.
Without Consent Mode V2 you don’t lose a technical feature. You lose data to measure and advertise on Google Ads.
What Consent Mode is and why it becomes mandatory
It is a Google tool, launched in 2022. It connects to your site’s cookie banner and tells Google what level of consent the user has given. With that information, Google tags run within the law instead of going their own way.
Version 2 goes further. It governs not only what data is collected, but how it is used and how it is shared. To keep advertising on Google Ads you need a Google-certified consent management platform (CMP). Without that piece, the loop doesn’t close.
Why it’s worth adapting
V2 introduces two new signals, ad_user_data and ad_personalization, which are the ones that allow you to build audiences and run remarketing. It also brings an advanced mode with pings that send aggregated data even when there is no explicit consent. In business terms: you keep the ability to segment and to win back users who have already visited you.
Which banner you need
It depends on how far you want to go. For an advanced setup you need a banner from a Google-certified CMP. For a basic setup, you can use a custom one.
If you already have a verified CMP, you save on development. Cookiebot, CookieScript and CookieYes are three options that are already recognised. If you don’t have one, now is the time to set one up.
When third-party cookies fall, your own data stops being an extra and becomes the asset.
What happens if you do nothing
An early analysis puts numbers on it. Users without cookies show an estimated 30% worse advertising performance. That means paying the same for less return, and measuring every euro you invest less accurately.
The conclusion is simple. Staying up to date isn’t an optional upgrade, it’s what lets you keep competing with the same tools as everyone else.
Frequently asked questions
What is Consent Mode V2?
It is the updated version of Google’s tool that communicates the user’s consent. Unlike the first one, it governs both the collection of data and how it is used and shared.
Why has Google updated it?
To adapt to the EU’s DMA and the demise of third-party cookies. Without this update, its advertising tools would not comply with European regulation.
How do I implement it?
You need a Google-certified CMP connected to your cookie banner. The CMP gathers consent and passes it to Consent Mode, which adjusts how Google tags behave based on the user’s response.
What benefits does it bring?
It lets you keep measuring, build audiences and run remarketing while staying within the law. You keep the ability to segment and win back users even in a world with fewer cookies.
What happens if I don’t update?
You lose the ability to collect and use data for Google Ads. In practice, you measure worse and your advertising performs worse.
This article is from 2024. Google changed its plans afterwards: we tell you what really happened in Third-party cookies aren’t dead.
Where Undercoverlab fits in
We implement Consent Mode V2 end to end. We pick the CMP that suits you, connect it to the banner and check that the data arrives where it should, within the rules. If you want a review of how your consent is set up, we’ll look at it.
