Three essays in economics of online advertising.

Summary The thesis presents an economic analysis of three new topics related to the economics of online advertising. It uses both empirical and theoretical methods. Chapter 1 presents the background of the thesis as well as the main results developed in the following chapters. In chapter 2, the thesis shows through a theoretical model how transparency in the modes of advertising purchases modifies the market equilibrium. In a context where advertising is considered a nuisance by users, the chapter shows that the introduction of such transparency-enhancing technologies can affect welfare in different ways. Chapter 3 discusses the economic relevance of profiling technologies that allow websites to adapt their level of advertising to the user's sensitivity. The chapter builds a theoretical model and draws the main implications arising from the use of these technologies. In Chapter 4, the thesis highlights how a privacy policy that allows users to opt out of ad targeting can have economic implications in the online advertising market. The chapter presents a new computational methodology and estimates the impact of such a privacy policy on ad prices. The results differ from previous work and show that the impact depends strongly on the characteristics of the website as well as the attractiveness of other sales channels. Finally, Chapter 5 concludes by highlighting how the key points developed throughout the chapters have significant economic weight.