We investigate the impact of the recently introduced European (EU) General Data Protection Regulation (GDPR) on the advertising-supported online ecosystem, with a specific focus on online content providers and their users. Our study integrates different streams of literature to provide empirical evidence on a hotly debated topic in the privacy literature: namely, to what extent the tracking of online users and the mining of their private information is, or is not, necessary to sustain the provision of free online content and services.