The GDPR regulates at present the handling with personal data fundamentally new and thereby opens new leeway. At the same time, it creates great uncertainty among those affected. One example of this is web tracking: It helps designers to improve the utility and usability of their websites based on, in part, extensive (personal) data collection, or enable operators to finance them. Against this background, in this article we first show the practical relevance of web tracking by collecting the web trackers of the 100 most popular pages of each of the 28 EU member states. Building on this, we show which data these trackers collect and analyze their legal bases. Finally, we discuss possible consequences in design and architecture for fulfilling the legally outlined requirements, taking into account a user’s perspective.