Top 100 websites in UK, US and AUS dependent on third-party cookies

top 100 websites and cookies

New research carried out by DMPGObservePoint, and Similarweb, has revealed a significant dependency on third-party cookies across UK, US and Australia’s top 100 websites.

Top 100 websites

An average of 81 of the leading 100 sites set cookies in a third-party context.

The research uncovered that the majority of third-party cookie domains identified support advertising technology. 

Across the three regions, these accounted for 84.9% of the third-party domain counts. 

While the dependency on third-party cookies is much lower for the other non-advertising categories, the report highlights sites among the top 100 that still have dependencies on other technologies for things like measurement, site personalisation, and other functionality such as surveys, live chat, and sharing. 

There were even a few sites which had necessary functionality with third-party cookie dependencies relating to login and payments.


For the UK, advertising tech accounted for almost eight in ten (79%), the lowest percentage of sites between the other markets, with advertising-dependent third-party cookies. 

The UK had the highest percentage 8.3% in comparison to the US and Australia on third-party cookies linked to measurement.


In Australia, advertising tech accounted for nearly nine in ten (87.7%) of third-party cookie domain counts, the highest of the three regions. 

A further 6.9% were used for measurement and personalisation, while 2.2% were functional and related to live chat, social sharing buttons and web surveys. 

A small number of websites were found to have third-party cookie dependencies for necessary functions relating to login and payments. 

The average number of cookie domains per single site is 21, with 39 unique cookie names across the top sites. The maximum number of cookie domains counted on a single site was 84.


The US had the second-highest advertising category dependency of eight in ten (86%). It also had the second-highest dependency on third-party cookies which were linked to measurement 6.2 %.

Steve Carrod, Co-Founder and Managing Director, DMPG, commented: “The fact that there is still such a large dependence on third-party cookies does not come as a surprise. 

“We saw a general lack of urgency to adjust to regulations imposed by GDPR, which were in part down to the confusing messages delivered by regulators in this area. 

“The changes that are impacting our — as brand owners — ability to track customers across domains are not going to be any easier to work with. 

“In actual fact, I predict that there will be a very significant and disruptive battle for dominance between Facebook, Google, Apple and Amazon. 

“Each will want to take a dominant role in terms of their position around who owns the customer and how they can be communicated with, which is unlikely to align with how the brand owners will want it to happen.

“While there are no silver bullets to resolve the situation we are currently in, brands must not hesitate in terms of taking action to put themselves in the best possible position to weather the changes to this industry that will be happening over the next few years. 

“The one overriding piece of advice we are giving anyone is to focus on your customers. Put their needs first, be transparent about what you need their data for and how you will use it.  

“Explain the benefits that will be given to them if they share it with you. This will help ensure that you find yourselves in a position where you do not need to be reliant on third-party data of any kind.”

Research into websites

In order to conduct the research, Similarweb provided the rankings data for the top 200 domains for each region based on site traffic. 

Adult sites were removed from the rankings data, as were sites that blocked crawling tech. 

ObservePoint crawled each of the top 100 domains to uncover which cookies each site used. After extracting the data, ObservePoint and DMPG collaborated to categorise the cookies and analyse the data.

The full report can be found here, and a recording of a webinar hosted by ObservePoint and DMPG to discuss the findings can be found here.