Before and After GDPR: The Changes in Third Party Presence at Public and Private European Websites

The commencement of EU's General Data Protection Regulation (GDPR) has led to massive compliance and consent activities on websites. But did the new regulation result in fewer third party server appearances? Based on an eight months longitudinal study from February to September 2018 of 1250 popular websites in Europe and US, we present a mapping of the subtle shifts in the third party topology before and after May 25, 2018. The 1250 websites cover 39 European countries from EU, EEA, and outside EU, belonging to categories that cover both public-oriented citizen services, as well as commercially-oriented sites. The developments in the numbers and types of third party vary for categories of websites and countries. Analyzing the number of third parties over time, even though we notice a decline in the number of third parties in websites belonging to certain categories, we are cautious about attributing these effects to the general assumption that GDPR would lead to less third party activity. We believe that it is quite difficult to draw conclusions on cause-effect relationships in such a complex environment with many impacting factors.