Adsense history

Oingo, Inc., a privately held company located in Los Angels, was started in 1998 by Gilad Elba z and Adam Weiss-man. Oingo developed a proprietary search algorithm that was based on word meanings and built upon an underlying lexicon called Word-net, 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 Ad Sense program in March 2003 and made it public in June of that year. Some advertisers complained that Ad-sense yielded worse results than Ad-words, 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 Ad-sense network
By early 2005 Ad-sense accounted for an estimated 15 percent of Google's total revenues
In 2009, Google Ad Sense announced that it would now be offering new features, including the ability to "enable multiple networks to display ads".
In February 2010, Google Ad Sense started using search history in contextual matching to offer more relevant ads.