GOOGLE ADSENSE

Google AdSense is an ad serving application run by Google Inc. Website owners can enroll in this program to enable text, image, and video advertisements on their websites. These advertisements 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$2.34 billion ($9.36 billion annualized), or 28% of total revenue, through AdSense. 

Google uses its Internet search technology to serve advertisements based on website content, the user's geographical location, and other factors. Those wanting to advertise with Google's targeted advertisement system may enroll through Google AdWords. AdSense has become a popular company in creating and placing banner advertisements on a website, because the advertisements are less intrusive than most banners, and the content of the advertisements is often relevant to the website.

Many websites use AdSense to monetize their content; it is the most popular advertising network. AdSense has been particularly important for delivering advertising revenue to small websites that do not have the resources for developing advertising sales programs and sales people to generate revenue with. To fill a website with advertisements that are relevant to the topics discussed, webmasters place a brief HTML code on the websites' pages. Websites that are content-rich have been very successful with this advertising program, as noted in a number of publisher case studies on the AdSense website. AdSense publishers may only place three ad units per page.