In 2007, U.S. advertisers spent US $24.6 billion on search engine marketing. In Q2 2015, Google (73.7%) and the Yahoo/Bing (26.3%) partnership accounted for almost 100% of U.S. search engine spend. As of 2006, SEM was growing much faster than traditional advertising and even other channels of online marketing. Managing search campaigns is either done directly with the SEM vendor or through an SEM tool provider. It may also be self-serve or through an advertising agency. As of October 2016, Google leads the global search engine market with a market share of 89.3%. Bing comes second with a market share of 4.36%, Yahoo comes third with a market share of 3.3%, and Chinese search engine Baidu is fourth globally with a share of about 0.68%.
In the parlance of digital marketing, advertisers are commonly referred to as sources, while members of the targeted ads are commonly called receivers. Sources frequently target highly specific, well-defined receivers. For example, after extending the late-night hours of many of its locations, McDonald's needed to get the word out. It targeted shift workers and travelers with digital ads, because the company knew that these people made up a large segment of its late night business. McDonald's encouraged them to download a new Restaurant Finder app, targeting them with ads placed at ATMs and gas stations, as well as on websites that it new its customers frequented at night.