What is Adsense

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 by Google and 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 2010, Google earned US$2.04 billion ($8.16 billion annualized), or 30% of total revenue, through AdSense.

How AdSense works 

• The webmaster inserts the AdSense JavaScript code into a webpage.
• Each time this page is visited, the JavaScript code uses inlined JSON to display content fetched from Google's servers.
• For contextual advertisements, Google's servers use a cache of the page to determine a set of high-value keywords. If keywords have been cached already, advertisements are served for those keywords based on the AdWords bidding system. (More details are described in the AdSense patent.)
• For site-targeted advertisements, the advertiser chooses the page(s) on which to display advertisements, and pays based on cost per mille (CPM), or the price advertisers choose to pay for every thousand advertisements displayed.
• For referrals, Google adds money to the advertiser's account when visitors either download the referred software or subscribe to the referred service.The referral program was retired in August 2008.
• Search advertisements are added to the list of results after the visitor performs a search.
• Because the JavaScript is sent to the Web browser when the page is requested, it is possible for other website owners to copy the JavaScript code into their own webpages. To protect against this type of fraud, AdSense customers can specify the pages on which advertisements should be shown. AdSense then ignores clicks from pages other than those specified.

Abuse

Some webmasters create websites tailored to lure searchers from Google and other engines onto their AdSense website to make money from clicks. These "zombie" websites often contain nothing but a large amount of interconnected, automated content (e.g., a directory with content from the Open Directory Project, or scraper websites relying on RSS feeds for content). Possibly the most popular form of such "AdSense farms" are splogs (spam blogs), which are centered around known high-paying keywords. Many of these websites use content from other websites, such as Wikipedia, to attract visitors. These and related approaches are considered to be search engine spam and can be reported to Google.^{[citation needed]}
A Made for AdSense (MFA) website or webpage has little or no content, but is filled with advertisements so that users have no choice but to click on advertisements. Such pages were tolerated in the past, but due to complaints, Google now disables such accounts.
There have also been reports of Trojan horses engineered to produce counterfeit Google advertisements that are formatted looking like legitimate ones. The Trojan uploads itself onto an unsuspecting user's computer through a webpage and then replaces the original advertisements with its own set of malicious advertisements.

 Here i will show you picture of check from "Google"