Although a few global search engine platforms, notably Google and Yahoo!, have overall worldwide dominance in the search engine market, some domestic search engine platforms, such as Naver in South Korea and Baidu in China, have competed against global search engines and have dominated their domestic search engine markets. In this study, we tried to quantify the economic effects of the existence of domestic search engines on the development of the online advertising market. To do this, we constructed a country-level dynamic panel of 46 countries based on industry and government sources from 2009 to 2013, which included the individual country trends of online advertising markets, country-specific economic and cultural status, broadband Internet penetration, and other indexes indicating the development of information and communication technologies. We then investigated the change in the size of the online advertising market caused by the existence of a domestic search engine. Our analysis shows that the development of a domestic search engine may lead to an increase in online advertising revenue: A country with its own domestic search engine platform(s) may have 0.018% more online advertising intensity—which is defined as online advertising spending/GDP—than one without this type of platform. This result confirms the hypothesis that a domestic search engine has a positive effect on the development of the domestic online advertising market. The reasons behind this trend and policy implications are also discussed.