The Functional Role of Personal Data in Digital Service Transactions: Property Implications and Platform Obligations in Private Law

Digital services are increasingly supplied in exchange for personal data rather than money. This Article examines the functional role of personal data, using European Union law as its principal doctrinal reference and Vietnam as an illustrative case study. Rather than treating personal data as property, it argues that private law should focus on its functions in digital exchange. Personal data operates as contractual counter-performance, a productive asset, and a source of platform power, generating property-like implications without requiring full propertization. The Article develops a functional private-law framework for platform obligations and contributes to contemporary debates on data-based contractual exchange.