U.S. Digital Advertising Landscape And Key Players (Part 2)

The online advertising market is concentrated – the 10 leading ad-selling companies comprised 71% of total revenues in Q4 2014. This came in similar to the level seen in Q4 2013. While, Google, Microsoft (Bing), Yahoo, and AOL are the most dominant players in the search engine verticals, Facebook, Google, Twitter and Yahoo lead the display ads business. Google leads the U.S. search market with 64% share.

http://www.forbes.com/sites/greatspeculations/2015/07/09/u-s-digital-advertising-landscape-and-key-players-part-2/