Over the past decade, successive steps have been taken to empower individuals with new legal and technical means, from smart disclosure initiatives to the right to data portability of the GDPR and the new notion of data altruism enacted in the EU [5]. The ultimate goal is to enable individuals to collect and share their personal information, for their own good and broader societal benefits, unlocking innovative usages when crossing multiple data sources from one or many users. The technical corollary of this movement is the emergence of personal data management systems (PDMS) that allow individuals to assemble their personal data under their control, with products such as Digi.me, Cozy Cloud or Solid/PODS, as well as initiatives like Mydata.org, supported by data protection agencies.