• Airbnb
• algorithmic governance
• algorithms
• artificial intelligence
• automated decision-making
• balancing of interests
• BlaBlaCar
• collaborative economy
• Court of Justice of the European Union
• data protection authorities
• digital platforms
• digital surveillance
• fundamental rights
• GDPR
• legitimate interest
• personal data protection
• platform capitalism
• privacy policy
• profiling
• sharing economy
• surveillance capitalism
• Uber

Behind the collaborative rhetoric of platforms like Uber, Airbnb, and BlaBlaCar lies a sophisticated data extraction apparatus that transforms every user interaction into commercial intelligence. This thesis exposes the fundamental incompatibility between these platforms' surveillance-driven business models and EU data protection principles, revealing how legitimate interest has become a legal front for systematic privacy erosion. Through analysis of CJEU jurisprudence, EDPB guidelines, and enforcement actions, this research demonstrates that collaborative platforms systematically fail to meet legitimate interest requirements: genuine legitimacy, strict necessity, and proportionate balancing. The investigation uncovers how AI and automated decision-making systems function as instruments of digital control that reshape labour relations and social interactions. By examining privacy policies and enforcement patterns, the study reveals corporate strategies designed to maximise data utility whilst maintaining superficial regulatory compliance. The research challenges the assumption that commercial interests can be reconciled with individual autonomy under current frameworks, arguing that legitimate interest requires recalibration to prevent its transformation into a blank cheque for surveillance capitalism.