Your cookies aren’t going anywhere. Third-party cookies are.

Written by Adrian Grigore

Your media agency will have probably told you that cookies are being deprecated in 2024. Hopefully, they added some nuance to that. If not, read on...

It’s simultaneously less bad and worse than you think. Depending on how your marketing corps are set up, the changes may not affect you at all.

Cookieless isn’t exactly… cookieless.

A quick web search for ‘cookieless marketing’ yields several articles that bemoan the loss of cookies and make it sound like third-party cookies are the only marketing-related cookies you should care about. That is if they bother to mention that only those cookies are being deprecated.

Cookies only your company can read and use (first-party cookies) are staying. Your analytics, CRM, and A/B testing tools will not be more broken than they already are.

Most of the discourse is concentrated on marketing sites – entities with a vested interest in keeping the technology alive (since that’s how they’re making money). So, let’s shift focus on the technology and go through what Mozilla Developer Network has to say about it:

Third-party components can store information in their cookies from any and all documents they are embedded in. The originating third-party domain can then get access to all those third-party cookies, aggregating information from each one.

The magic of targeting and retargeting is predicated on the above behaviour – the ability of a DSP/ Advertising Network to follow users across multiple domains and stitch together their digital identity and preferences/ topics of interest. The article linked above goes into more detail regarding how this can lead to unwanted results, so we won’t focus on those.

The market leader is just following the market

I mentioned in a December 2023 blog post that what’s actually happening is that the leader (by market share) has just now decided to follow the market – most major browsers already reject third-party cookies. To quote Jason Packer, “Unless you run an ad network, there’s no reason to panic”.

But while non-Google browsers simply reject them, Chrome replaces them with its Privacy Sandbox – a piece of tech that promises to capture user behaviour and interests in a more private way (hence the name), without leaking the user’s actual identity. This sounds good, but only on the surface. Privacy Sandbox implies:

The above can only lead to a centralisation of power into Google’s hands – surely an accident.

Costs may rise, but ROI may not

GDPR impacted third-party cookies early on. An August 2018 report from Reuters Institute showed a 22% drop in the number of third-party cookies loaded on news sites (and similar) in the three months since GDPR went into effect. Users are so good at rejecting cookies altogether, or blocking trackers, that whatever behavioural data you do have is probably rubbish. So, there’s not much of a loss, but your mileage may vary. tried going almost completely cookieless (that includes its first-party cookies as well) and saw its retargeting obliterated and paid search costs go up.

… When comparing period over period from before we removed user tracking and cookies on our site to after, we saw around a 30% increase in our cost per click (CPCs) in Google search.

Bear in mind that period over period is not necessarily a good comparison, especially in high-seasonality markets.

Sentry’s Display conversions also dropped.


These conversions weren’t converting through our funnel to paying customers at a high enough rate anyway (even with a long-term view)

This is definitely a familiar tune – high conversion channels don’t always translate to good pipeline, and it may have to do with the kinds of users who reject tracking. You end up with a self-selected pool of people who are either fine with being tracked or oblivious to it. Not to mention… bots. Ad Fraud made up 22% of Ad spend in 2023.

Where to next?

Your best bet is to start small – make incremental changes to your martech and paid media strategies, and see what works best. Here are some ideas to get you started:

  • Accept that multi-channel, cross-device attribution is likely broken or inaccurate and switch to Last Click (for automated reports). Last Click would paint an incomplete picture, but an honest one

  • Include attribution questions in your marketing automation flows

  • Target based on content topic(s) rather than user interest

  • Lean into platforms (LinkedIn & Facebook Lead Gen, 6sense’s DSP)

  • Leverage first-party data with consent (e.g. retarget based on email hashes)

  • Work from a Target Account list (so you can advertise to roles within a company)

  • Have Sales & Marketing share insights more often

  • Look into adopting ABM or ABM-like strategies

  • Consider testing a Demand Gen approach

  • Make use of Data Enrichment tools

  • Review marketing campaigns based on your average business cycle length (e.g. look at cohorts brought in by Q1’s campaigns and compare them to Q2’s campaign cohorts)

  • Evaluate if Media Mix Modelling is right for you

  • Revise your Experimentation methodologies (or adopt some)

If you’d like to have a more in-depth look at how you can be preparing for the future, please register your interest here.



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