Removing the parameters isn't the only adjustment Apple has made in Safari's Private mode. The new version also blocks a lot of Google marketing tooling. This blocks Google Tag Manager in its entirety, and with that all tags implemented via GTM. In addition, we see that Google Analytics, Google Ads and Facebook Ads, implemented outside of GTM, are also blocked.

In recent years, we've seen similar changes in Safari and Firefox — and Chrome is soon to follow suit. Big tech companies are adapting their tools and platforms to take more account of their users' privacy. That's a clear movement in digital marketing — and specifically tracking — that marketers need to be more aware of now than ever before.

It’s especially important for marketers to remember that tracking on an individual level is increasingly protected. All reports, dashboards, and models that work at the individual level will have to take these adjustments into account (which is unlikely to decrease in the coming years). The arrival of Google's Privacy Sandbox will undoubtedly open a new chapter. You have to think of attribution models, user reports (e.g., returning visitors) but also A/B testing and personalisation.

The impact of directly blocking tools such as Google Tag Manager, Google Analytics, Google Ads and Facebook ads is clear. None of the tools will be able to collect data anymore. 

The disappearance of these parameters needs a little more explanation. This also affects the way we measure and target ads. We use tracking parameters to track: 

• How much traffic goes to a website via which campaign 

• Which campaigns are successful 

• Which target groups respond 

• How many conversions we get 

We can do this because parameters connect information from advertising sources and websites. In the most advanced parameters, you will even find information that you can trace back to the individual level. Now that those parameters are disappearing, it becomes more difficult to collect that valuable information. Or, in other words: to know which of your marketing efforts really work. 

In order to provide concrete insights into the technical impact of these changes, we distinguish between different customer journey stages: 

1.     Ads 

2.     Website/webshop 

The impact can be felt in advertising and web analytics tooling, as the illustration below indicates. 

In terms of advertising, this impact mainly comes on the use of data about individuals. Data from aggregated numbers (such as number of visitors, behaviour, and conversions) is unaffected. What is limited now is the use of information about the individual for audience or retargeting purposes. 

In terms of web analytics, the auto-tagging feature via GCLIDs of Google Analytics and Google Ads is compromised. Because Google Ads source recognition is eliminated with auto-tagging, it becomes more difficult to see which channel your traffic is coming from and to analyse subsequent behaviour. For now, these adjustments will only affect traffic using Safari Private Browsing. 

On paper, this update is bad news for our web analytics measurements, associated attribution models, and retargeting initiatives. But it's important to remember that so far, the change only applies to Safari private mode. Of course, it is still bad news for marketers, but it’s important to retain a realistic picture of the impact. 

Let's start with the overall numbers. About 25% of internet users in the Netherlands use Safari — in Belgium this is about 15%. In general, only about 20% of traffic uses private or Incognito mode. Based on these figures, we will miss out on potential insights for an average of 3 to 5% of traffic. For the parameters, this figure only applies to traffic from advertising. 

Then the question may arise: when am I going to see the impact of this reflected in the figures? According to Mixpanel, with iOS 16, it took about two months for 50% of users to update, and three months for this group to rise to 67%. 

Apple's update is part of a growing series of similar changes. So it's best to look at solutions in a broader perspective, so that you think about a future-proof tracking architecture. Some possible solutions: 

1.     Falling back on UTM tagging: The biggest impact can be seen in web analytics attribution tracking, as advertiser parameters disappear. UTM tagging does not contain information at an individual level and will continue to work. So get your UTM tagging back in order for your advertising in the short term.  

2.     Server-side tracking: Especially for blocking Google Tag Manager, Google's server-side Tag Management is a solution.  
The 'new pain' is less tangible in advertising tools, but it’s worth taking a critical look at your advertising pixels. If they are still implemented client-side, then there is also a gap in your data. Cookies are blocked or discarded faster by browsers, but there are solutions for that. Server-side tracking is a strong addition to your future-proof tracking stack.  

3.     Marketing Mix Modelling: Tracking will continue to change, and individual tracking in particular will become more difficult. So look at other solutions, such as Marketing Mix Modelling — an important alternative to attribution models. MMM uses data at an aggregate level and is therefore a perfect alternative to models that use user-level data.  

4.     Focus on first-party data via Enhanced Conversions / Advanced Matching: Providers of advertising tools are not sitting on their hands and are devising new ways to be less reliant on parameters and third-party cookies. Facebook and Google have both launched an option to share first-party data — Advanced Matching and Enhanced Conversions, respectively. They collect data directly from the website visitor (such as e-mail addresses and preferences) and share it with the vendors. Then the match is made with that data, instead of parameters.  

5.     Consent mode: Google introduced this functionality in response to the growing enthusiasm for privacy regulation. The internet giant is coming up with alternatives such as consent mode to fill in the new gaps. Consent mode can model data that is missing in Google Analytics and Google Ads, through consent choices made. After all, Google knows exactly how many users have not given permission to be tracked via the consent mode.  

In summary, iOS 17 presents definite challenges for marketers. But with the right adjustments and strategies, you can still run successful campaigns and reach your audience — even without tracking parameters in Safari private mode.