The PPC industry was pioneered by GoTo.com (later re-branded as before it was purchased by Yahoo! in July 2003). Despite their enormous success, Go To's PPC model was met with a lot of skepticism in the industry following their IPO in 1999. Their eventual purchase by Yahoo put to rest any doubts that pay per click advertising was here to stay.
In October 2000, which was eventually to become the world's most popular search engine, their own keywords advertising model (Google Ad Words), blending algorithmic search results with pay per impression ads.
In 2002, in an attempt to compete more successfully with Overture, Google Ad Words to include the pay per click pricing model we are familiar with today. This model proved both more popular and more successful and eventually replaced the pay-per-impression model as the default system.
By 2002, GoTo (by then rebranded as Overture), had distribution deals with an impressive range of search engines including Yahoo!, MSN, AltaVista, InfoSpace and a number of meta search engines including MetaCrawler and Ixquick. Overture's powerful distribution network guaranteed advertisers placement of their ads in front of a LOT of eyeballs and it became clear that many were willing to pay big bucks for the privilege. Other major search engines also formed successful distribution partnerships with PPC providers during this time, noticeably AOL, AskJeeves and MSN with Google AdWords. The pay per click industry had officially arrived.Scores of PPC search engines began to spring up following Overture's lead, however the PPC industry continued to be dominated by the two big PPC players, Overture and Google AdWords, while Yahoo!, MSN, AOL and Google fought it out for dominance in the general search market
In July 2003, in a move that shocked the industry, Yahoo! purchased Overture to enable them to better compete with market leader Google. In April 2005 they the PPC engine as and in 2006 they a revamped version of the service, code-named Panama.
Meanwhile, in October 2005, Microsoft called . In the US, together with a name change to Microsoft AdCenter occurred in May 2006. In May 2007, Microsoft revamped AdCenter with new features and to advertisers worldwide.