Antitrust enforcement in digital and high-tech markets is not disconnected from traditional antitrust theory or practice. Yet, unique features of firms operating in digital and other high-tech markets can necessitate modification of doctrine. For example, modern antitrust enforcement in digital markets needs to take seriously the presence of network effects in two-sided markets and the procompetitive justifications for various kinds of product design decisions that may otherwise appear to harm competitors under older models of antitrust enforcement. The goal, however, remains enforcement of the consumer welfare standard, even if enforcers and courts must be sensitive to features particular to digital markets.This chapter takes the 2001 D.C. Circuit opinion in Microsoft as an inflection point in digital antitrust enforcement. With that case we can first clearly see all of the various threads pulled together that run through modern antitrust enforcement in high tech cases. This chapter begins with a brief overview of the precursor cases that informed enforcement up until the late 1990s before devoting attention to Microsoft and the subsequent cases that shape modern antitrust enforcement in digital markets.

Exemptions and immunities limit the reach of the antitrust laws. If the courts and agencies implement exemptions and immunities too expansively, anticompetitive conduct will elude enforcement and thereby injure consumers. The dynamic nature of the digital economy amplifies these concerns. Policymakers, courts, and regulators must diligently assess the ever-changing digital landscape and tailor antitrust doctrine accordingly.

In Section I of this paper, I examine the origins or seeds of precautionary antitrust by revisiting enforcement by European administrative competition agencies in digital markets. In Section II, I explain how this ideology was embraced, advocated, and advanced in several “tech reports” representing the blossoming of the precautionary principle. I conclude in Section III, by proposing the reinstatement and further development of tools that protect the legal and economic rationale of antitrust, as recognized by European courts.

In this chapter, we discuss the development of the duty to deal doctrine in antitrust law, its application to the digital economy, and proposals for specific duties to deal, such as data portability and interoperability.Part I outlines the development of the duty to deal doctrine in antitrust law. The development of the doctrine in the United States will be compared to that in the European Union. Popular economic justifications for the doctrine and key cases will be explored. Part II then situates this doctrine within the digital economy, focusing on the importance of getting the contours of the doctrine right in that economy. As we shall see, the law and economics of the duty to deal caution against its application to dynamic, digital markets. This will be illustrated by looking at cases where it has been applied. Part III focuses on two specific categories of duties to deal: data portability and interoperability.

This Chapter discusses the theories behind the call to incorporate privacy into antitrust and identifies some potential legal and economic hurdles to their application. Chief among them are (1) the extent to which privacy is an important dimension of competition; (2) identifying the underlying anticompetitive conduct that gives rise to a reduction in privacy; and (3) understanding that the benefits and costs of data collection are inexorably intertwined, with the net impact of a reduction of privacy on consumer welfare depending on heterogenous tastes for privacy and customization that are likely to be correlated in complex ways. Further, this Chapter also addresses potential First Amendment issues raised by using antitrust to condemn certain types of data collection and use, as well as problems that may arise to the extent that incorporating privacy into antitrust renders liability standards more uncertain.

This paper examines the economics of digital platforms and two-sided markets and discusses the economic conditions that underlie policy assertions by advocates of both interventionist and laissez-faire policies. We include applications to internet search, online advertising, media, data, and privacy. Our goal is to provide a balanced look at the economic assumptions that underlie the many “possibility theorems” policymakers use to rationalize different policies (e.g., regulation, breaking up large companies, subsidizing entry, forced data sharing, or maintaining the status quo). Our discussion of the economics underlying various possibility theorems highlights the type of information and analyses required to determine whether alternative forms of intervention are likely to enhance the welfare of various market participants. While it is relatively easy to identify theoretical conditions under which intervention dominates the status quo (and vice versa), empirical verification is difficult because multi-sided platforms have many interrelated parts and involve complex data. These complexities augment the challenges inherent in implementing welfare-enhancing policies and highlight the importance of evidence-based decision-making.