Abstract
Browsing through social media posts is not an innocent activity and can have profound implications not just in relation to what products we would be offered next time we load the respective social media app but as the Cambridge Analytica scandal showed also in terms of important political processes and events. Chen starts the introduction to his book by discussing precisely the Cambridge Analytical scandal. He argues that one fundamental question was left unanswered, namely ‘even if the voting results were not affected by these campaigns, and even if Facebook users had given valid consent, should we allow fine-grained behavioural data to be used to exert political influence on our society’ (pp. 2–3). This is a question he addresses in his book, which focuses on online behavioural advertising defined as ‘the practice of presenting online marketing content to internet users based on the observation of their online behaviour’ (p. 3). Another key focus of the book is on data protection law. The book is split into four main parts. Part I, ‘The Set-Up’, includes two chapters providing the background information for the subsequent discussion. Part II, ‘The Stakes’, consists of two chapters on the benefits and risks of online behavioural advertising. Part III, ‘The Law’, comprises three chapters on data protection principles governing online behavioural advertising, lawful grounds legitimizing data uses for online behavioural advertising and the regulatory blind spots. Finally, part IV, ‘The Possibilities’, consists of one chapter on diversifying the regulatory toolbox and a conclusion.