A text-based advertisement service provided by Google.com.
Google AdSense is a popular way for websites to make money from advertisements, all the way from part-time bloggers to some of the largest publishers on the web. AdWords advertisers pay Google either by the click (PPC) or impression (CPM). In turn, Google shares a percentage of that revenue with the AdSense publishers.
Google AdSense serves ads via plain text, as opposed to graphical content that dominated the advertising scene when it was introduced in 2003. Google decided to serve plain text in an effort to minimize the intrusiveness of advertisements, to optimize the page loading speeds, and ultimately, to elicit a more favorable marketing response from the site visitor.
100% Google AdSense: Tools, Tips and Resources
Smashing Magazine (March 19, 2009)
Google Expands Advertising Monetization Program for Websites
Google (June 18, 2003)