How the death of third-party cookies will affect social media advertising

Goodbye third-party cookies, hello new advertising strategies.

For years, cookies have been the backbone for tracking your website visitors from across the internet.

As search engine users demand higher levels of privacy and transparency, this era is coming to an end – Google has announced plans to phase out all third-party cookies by 2024. It’s a move that will affect how many marketers advertise, including us!

Why? Because we use first-party and third-party cookies to help us understand who is searching for your business, where they are coming from, and, therefore, who to target your adverts towards.

Don’t panic though – we know that the key to not losing this vital data about your customers is to try and adjust the marketing strategy early. We know how, and if you read on, we’ll share our secrets.


First things first … what is a cookie?

I know what you’re thinking. A tempting little snack, full of gooey, chocolatey goodness. Sadly, these aren’t the cookies we are talking about.

Cookies are small text files that contain unique information that identifies your computer to a server. They have been around almost as long as the internet and were invented to streamline your experiences online.

There are two types of cookies:

  • First-party cookies: first-party cookies are created by the website you visit, and the data isn’t shared with other websites or advertisers. This type of cookie aims to improve your experience on a website, remembering useful information such as what language you speak, your personal information for filling out a form or what was in your basket previously.
  • Third-party cookies: third-party cookies are a tracking code placed on a domain (the name of the website you type into your browser) to collect data on your website activity. They learn about your online browsing and behaviours. Unlike first-party cookies, this data is shared across third-party domains via a tracking code. A common example of how this works is to imagine you recently looked into going to the theatre. You looked on several websites and checked out some reviews, but ultimately decided against going. A few days later, you find yourself being shown ads for theatre shows across your social media platforms. Coincidence? Think again. Your browser would have stored a cookie relating to theatre shows and is now using this data to show you targeted advertisements.


The good news is that first-party cookies are here to stay.

What will happen when third-party cookies are gone?

Once these cookies are phased out, conversion reporting will be less accurate. This is the step a user takes towards a purchase, such as a trial, a sign-up, or actually buying a product. Conversion data can track the effectiveness of your campaigns and help you to plan for the next one. Third-party cookies track these conversions by linking together a user’s activity on different websites.

Without third-party cookies, your conversions will not be tracked as accurately and won’t show up in your ad placements anymore, for example, Facebook business suite. They will instead be replaced by ‘machine-learning generated estimates’ – a fancy term for ‘a best guess’ at your total conversions.

Behavioural audience building could also become restricted. This technique uses data from third-party cookies to create user groups with similar behaviours and interests. This is commonly used within targeted advertising to ensure your products reach the right audience.

So what do you do?

Adjust your social strategy early to make use of other data sources

Luckily, for those who use meta-advertising, the meta pixel allows you to use both first- and third-party cookies. Combining both lets you reach more customers via meta and receive the most accurate reports and measurements. Once third-party cookies are phased out, you will still be able to make use of those first-party cookies when reaching your audience.

Get used to using first-party data

First-party data is an obvious solution in a world without third-party cookies. This data is collected directly from your website and is unique to each company. It can be gathered from first-party cookies and sign-up forms. This data type is more accurate than third-party cookies as it is collected directly from the source. First-party data is a privacy-friendly way to target specific audiences and track your conversions. Think email marketing, phone calls, and direct mail – go old school!

Get into the habit of using UTM parameters

If you get into the habit of using UTM parameters now, you can start to collect your data early. A UTM parameter is a short piece of text you can add to your website links. The five main parameters are source, medium, campaign, term, and content. These unique links can track how a site visitor has arrived at a specific landing page/your domain. For example, if you add ‘Meta Advertising’ to the source section of your UTM parameter, you will know that anyone visiting the site from that link will have come from your adverts on Meta. Using this method, you can discover how successful your call to action has been and adjust your adverts accordingly. It is also helpful when understanding your user’s journey, and you can use this data when planning your next campaign.

Say hello to conversion APIs

With the disappearance of third-party cookies, conversion APIs are a lovely option. These are set up on your server and allow you to send ‘events’, such as clicks on a contact form, directly from your server to third-party advertising platforms. As the data is on your server, you own it all – unlike a web pixel, which is client-side. This also means your conversion API is not limited by third-party cookies or browser settings.


In summary, with the end of third-party cookies comes the opportunity for new technology to emerge. Your business will be able to explore new advertising strategies and techniques, rather than relying solely on the data gathered from third-party cookies. It is vital that you test out different options and discover what works for your company before third-party cookies are removed so you can be prepared for the change.

Is all this cookie speak a bit too much to ‘digest’? Give us a call. Handling your marketing conundrums to make your life easier is what we do. That way, you can put the kettle on, sit back and enjoy an actual cookie!

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Emily sitting at her desk with a cup of tea.
Emily Davison
Digital Content Executive
Emily sitting at her desk with a cup of tea.

Article by:

Emily Davison -
Digital Content Executive

With three years of experience, Emily is the latest addition to our social media team. Emily’s main passion in life (other than TikTok) is a well-thought-out plan, which she uses to stay organised when working on campaigns for brands such as The Brighton Centre and our very own PMW accounts.

Outside of work, you will most likely find Emily doing something active. A lover of all things water, she kayaks, paddleboards, and even has a boat on the Norfolk Broads that she visits each summer with her family, friends, and lots of Aperol.

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