The document outlines the complex process of real-time bidding (RTB) in online advertising, highlighting the roles of supply-side platforms (SSP), demand-side platforms (DSP), and data management platforms (DMP). It discusses the significant volume of RTB transactions and emphasizes the issues of data leakage and GDPR compliance, particularly how personal data is processed without proper consent. Several examples illustrate the challenges and failures in adhering to privacy regulations within the RTB ecosystem.