[1] It can be argued that the ‘relative’ approach towards the notion of personal data finds support in previous case law of the Court of Justice as well. The Court of Justice has systematically ruled that it should be examined whether an entity has or may have the means reasonably likely to be used to identify the data subject. E.g. In Breyer, the Court of Justice concluded that the online media services provider had the means reasonably likely to be used to identify the data subject by pointing to the legal channels in the event of cyber attacks for accessing additional information enabling identification, held by the internet service provider (CJEU 19 October 2016, nr. Case C-582/14 Breyer, para 47). In IAB Europe, the Court of Justice concluded that IAB Europe had the means reasonably likely to be used to identify the data subject, because their members who held the additional information enabling identification, are required to provide IAB Europe with all relevant information upon request (CJEU 7 March 2024, nr. C-604/22 IAB Europe, para 48).
[2] European Commission, ‘A comprehensive approach on personal data protection in the European Union’ (Communication), COM (2010) 609 final, p. 5.
[3] See for example in the context of the right of access (EDPB, ‘Guidelines on data subject rights - Right of access’, 01/2022, 28 March 2023, para 188.)