For years, digital advertising relied on a simple assumption: that we can follow a visitor from the first click to the purchase. That assumption no longer holds. Browsers block third-party cookies, visitors must give consent before they are tracked, and many of them say “no”. The result is that many businesses see fewer conversions in their reports than they actually have – and make decisions based on an incomplete picture.

The answer is not to track more, but to measure better: with data that your own business collects, and with tools such as Consent Mode that respect each visitor’s choice. In this article we explain what first-party data and Consent Mode are, and which steps make your Google Ads campaigns and your analytics reliable again.

At a glance

First-party data is the data your own business collects directly from its customers, with their knowledge.
Consent Mode passes each visitor’s consent choice on to Google’s tags, which adjust accordingly.
For visitors from the European Economic Area, Consent Mode v2 is a prerequisite for remarketing and audience features in Google Ads.
A correct cookie banner comes first: without valid consent, everything else rests on weak ground.

What changed in measurement

Three things happened at the same time. First, browsers such as Safari and Firefox block third-party cookies by default, and many users add ad blockers on top. Second, European legislation requires consent before non-essential cookies are stored, so a share of your visitors is simply not recorded. Third, the advertising platforms adapted: Google now asks advertisers to send it each user’s consent choice in order to keep certain features available.

In practice this means that the numbers you see in your reports are no longer a complete count but a partial one. Whoever understands this and sets up measurement properly has a real advantage over competitors who continue as before.

What is first-party data?

First-party data is the information your own business collects directly from the people who interact with it: orders, contact forms, newsletter sign-ups, customer accounts, visits to your website. You collect it yourself, with the customer’s knowledge, and you know exactly where it came from.

Third-party data is the opposite: information gathered by someone else, across many websites, and sold or made available for advertising. This is the kind of data that is steadily disappearing.

	First-party data	Third-party data
Who collects it	Your own business	Other companies, across many websites
Examples	Orders, newsletter subscribers, forms, customer accounts	Interest profiles built from browsing history
Reliability	High: you know the source	Uncertain: you do not control how it was collected
Outlook	Becoming more valuable	Steadily shrinking

What is Consent Mode and how does it work?

Consent Mode is a Google mechanism that connects your cookie banner with Google’s tags (Analytics, Ads). When a visitor accepts or rejects cookies, the banner passes that choice on, and the tags adjust their behaviour: they use cookies only where consent has been given.

Its current version, Consent Mode v2, added two signals that concern advertising: whether the user’s data may be sent to Google for advertising purposes, and whether it may be used for personalised ads. Since March 2024, Google requires these signals for visitors from the European Economic Area. Without them, remarketing lists stop being filled with new users and conversion measurement becomes poorer.

There are two ways to implement it. In the basic implementation, Google’s tags do not load at all until the visitor consents. In the advanced implementation, when consent is denied the tags send limited signals without cookies, which allow Google to estimate with statistical modelling the conversions that would otherwise be lost. Which of the two suits you depends on your business and on the advice of your legal advisor.

6 steps to measure correctly

1. Start with a correct cookie banner

Non-essential cookies should be activated only after consent, and rejecting should be as easy as accepting: same level, same number of clicks, equally visible buttons. Prefer a consent management tool that is certified by Google and supports Consent Mode. A properly built banner is part of careful web design, not a detail added at the end.

2. Set up Consent Mode in Analytics and Google Ads

Connect the banner with your tags, ideally through Google Tag Manager, and check that the consent state is set before the tags load. Then test it: reject cookies on your own website and confirm that no advertising cookies are stored.

3. Enable enhanced conversions

With enhanced conversions, when a customer who has given consent completes a purchase or a form, their details (for example the email address) are sent to Google in hashed, unreadable form, so that the conversion can be matched to the ad that led to it. It is one of the most effective ways to recover conversions that are no longer recorded – we describe more in our step-by-step Google Ads guide.

4. Consider server-side tracking

In server-side tracking, measurement data is sent first to a server that you control and from there to the platforms, instead of directly from the visitor’s browser. It offers more reliable measurement and better control over what is shared, but it has a cost and needs maintenance. It is worth it mainly for online stores and businesses with a significant advertising budget.

5. Build your own audience

Every newsletter subscriber and every customer account is data that no browser change can take away from you. Give people a real reason to sign up – useful content, early access, an offer – and look after the list with a consistent newsletter. Our email marketing best practices are a good place to start.

6. Connect the data you already have

Orders in your online store, leads in your CRM, phone calls, visits to your physical store: when you connect them, you see the whole customer journey and not just the last click. You can also send sales that closed offline back to the advertising platforms, so that campaigns are optimised for real customers and not just for form submissions.

The most common mistakes

A banner that does not actually block anything. Cookies are stored before the visitor chooses, so the consent is not valid.
Consent Mode installed but never tested. The tags load before the consent state is set, and the signals reach Google incorrectly.
Decisions based only on the last click. With partial data, a single report rarely tells the whole story.
Collecting data with no plan to use it. A list that never receives anything useful loses its value.

Several of these appear in our list of digital marketing mistakes that cost you money.

What to keep in mind about legislation

The rules for cookies and consent come from European and national legislation, and data protection authorities carry out checks on websites. At European level a revision of the rules on cookie banners is under discussion, but until something changes, today’s obligations apply. This article describes good practice in measurement and is not legal advice: for your own case, consult your legal advisor or your data protection officer.

Why choose EasyMedia 360 Digital Agency

Correct measurement lies where the website, advertising and data meet. At EasyMedia 360 Digital Agency we handle them together:

Technical setup

Cookie banner, Consent Mode, Analytics and conversion tracking set up and tested as one system.

Campaigns that use your own data

Audiences and newsletters built on first-party data, with respect for each visitor’s choice.

Reports you can trust

A clear picture of what is measured, what is estimated and what it means for your decisions.

Frequently asked questions

Is Consent Mode mandatory?

It is not imposed by law; it is a Google requirement. If you advertise to visitors from the European Economic Area and want remarketing and audience features, in practice you need it.

Will I lose data if visitors reject cookies?

Some, yes. With the advanced implementation of Consent Mode and enhanced conversions, a significant part can be estimated or recovered, but no method brings back everything.

Does a small business need server-side tracking?

Usually not at first. A correct banner, Consent Mode and enhanced conversions cover most needs. Server-side tracking makes sense when the advertising budget justifies the cost.

Conclusion

Privacy did not end measurement; it changed its rules. Businesses that invest in their own data and in correctly configured tools see a truer picture and spend their budget more wisely. Start with the banner, continue with Consent Mode, and build step by step an audience that belongs to you.