110. There are barriers to entry in these advertising markets that protect Google’s advertising monopolies. Most critically, search advertising of any kind requires a search engine with sufficient scale to make advertising an efficient proposition for businesses. Specialized search engines require significant investment, including the cost of populating and indexing relevant data, distribution, developing and maintaining a search algorithm, and attracting users. Search advertising of any kind also requires (1) a user interface through which advertisers can buy ads, (2) software to facilitate the sales process, and (3) a sales and technical support staff. The same barriers to entry that apply to general search services also protect Google’s general search text advertising monopoly.
Declaring search advertising an illegal monopoly would not only open up the possibility for structural changes (requiring them to license the search advertising to other search engines, giving aggregators the ability to buy search advertising on google.com) but also exposes them potentially to large payments to advertisers who have been harmed in the past.