Adsense is a contextual advertising program by Google which allows website publishers to generate revenue from their sites by placing ads from the Google Adwords network on them. Each time these ads are clicked on by one of your visitors you earn a share of the revenue that Google makes from charging that particular advertiser.
Below is a summary of how the program works and the steps you will need to take to implement it.
1. You join adsense and on acceptance into the program become an Adsense Publisher. You will now have your own Adsense account in which you will be able to create the ad code to place on your website and monitor the results of your campaigns.
3. You can then place this code inside your website template: Make sure you've chosen an ad format which will fit into the space available in your template. Once you have uploaded your page to your server the Adsense ads will automatically be generated.
4. Google's content matching technology will deliver ads that are relevant to the page content you have placed the code on: It may take anywhere from a few minutes to an hour but Google will start delivering ads that match your content. This is the real perk of Adsense - ads that match the content of your page so that they are relevant to what your visitors are reading and thinking about at the time and so more likely to be clicked on.
In Google's own words:
"Google AdSense™ automatically delivers text and image ads that are precisely targeted to your site and your site content—ads so well-matched, in fact, that your readers will actually find them useful"
For more information on where the ads actually come from and how which ads appear is determined take theAdsense Tour.