As first glance, this seems like a tough position to defend. There's a sharp difference between how companies use mass market tools like billboards and how they use search-based advertising, which targets consumers far closer to the point of sale. And even if you buy Google's claim that the lines between media have been blurred by technology, it's still hard to explain how the company could maintain a 30 percent operating margin, despite money-losing outlays in a host of adjacent fields, if it faced serious competition. As Wagner himself notes, arguing that Google's market is broader than search advertising is not intuitive. When Microsoft tried to argue that it didn't have a monopoly in the 1990s, that strategy was widely seen as disingenuous.