Abstract
Attempts to temper big technology firms’ outsized influence in online advertising demonstrate a convergence of opinions between experts as to the extent that the activities of such companies impinge on aspects of citizens’ lives, ranging from the loss of privacy to instances of exclusionary behaviour by incumbents drawn up to handicap competitors. But cutting back big technology firms’ influence through competition law risks inconsistency when different values such as privacy and competition are engaged. This article presents a taxonomy of competition enforcement strategies that can help navigate disputes in online advertising. It reveals that most inconsistencies are the result of an effort in competition policy to divide up separate competition enforcement strategies into mutually exclusive accounts. If these accounts are viewed as complements rather than as substitutes, most inconsistencies disappear. The article offers a shared understanding of competition law and data privacy and seeks to cultivate a more cohesive and nuanced policy debate.