That allows publishers in the Google Network of content sites to serve automatic text, image, video, and rich media adverts that are targeted to site content and audience. These adverts are administered, sorted, and maintained by Google, and they can generate revenue on either a per-click or per-impression basis. Google beta-tested a cost-per-action service, but discontinued it in October 2008 in favor of a DoubleClick offering (also owned by Google). In Q1 2011, Google earned US $2.43 billion ($9.71 billion annualized), or 28% of total revenue, through Google AdSense.
Oingo, Inc., a privately held company located in Los Angeles, was started in 1998 by Gilad Elbaz and Adam Weissman. Oingo developed a proprietary search algorithm that was based on word meanings and built upon an underlying lexicon called WordNet, which was developed over the previous 15 years by researchers at Princeton University, led by George Miller.
Oingo changed its name to Applied Semantics in 2001, which was later acquired by Google in April 2003.
Google launched its AdSense program in March 2003 and made it public in June of that year. Some advertisers complained that AdSense yielded worse results than AdWords, since it served ads that related contextually to the content on a web page and that content was less likely to be related to a user's commercial desires than search results. For example, someone browsing a blog dedicated to flowers was less likely to be interested in ordering flowers than someone searching for terms related to flowers. As a result, in 2004 Google allowed its advertisers to opt out of the AdSense network.
By early 2005 AdSense accounted for an estimated 15 percent of Google's total revenues.
In 2009, Google AdSense announced that it would now be offering new features, including the ability to "enable multiple networks to display ads".
In February 2010, Google AdSense started using search history in contextual matching to offer more relevant ads.
