Google AdSense

Google AdSense is a program run by Google that allows publishers in the Google Network of content sites to serve automatic text, image, video, or interactive media advertisements, that are targeted to site content and audience. These advertisements are administered, sorted, and maintained by Google. 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 2014, Google earned US $3.4 billion ($13.6 billion annualized), or 22% of total revenue, through Google AdSense. Over 14.3 million websites use AdSense.
Google AdSense is a program run by Google Inc. which enables publishers in the Google Network of content sites to automatically serve text, image, video, and rich media ads that are targeted to site content and audience. These advertisements are administered, sorted, and maintained by Google, and they can generate revenue on either a per-click or per-impression basis.
7 steps to become an affiliate with Google
In order to promote any opportunities within the Google Affiliate Network on your website, you must complete three initial steps.
First, you will have to go Google Affiliate for Publisher. You can sign up here: http://www.google.com/ads/affiliatenetwork/publisher/
Before signing up, you should already have a Google AdSense account PUB ID and AdSense e-mail ID.
Click the sign up link, and then click the “Yes, I have an AdSense Account” button.
Then provide your AdSense e-mail and AdSense Publisher ID to complete your Google Affiliate Network profile. This will initiate the link between your AdSense and Google Affiliate Network accounts, and to confirm the AdSense account where Google Affiliate Network will post your earnings. Click the “Submit & continue” button.
Next, submit information about your website or blog, contact information, promotional methods, and agree to the policies and Program Terms and Conditions.
Google Affiliate Network team will then reply via email after 2-3 days on whether your application has been approved or denied. Most applications do get approved.
You’ll then have access to all the Google Affiliate tools in your account. Sign in, click on then advertisers tab and select all available products. This is where you can search through and decide which product or company you want to be affiliated with and promote on your own website. Once you find a product or company, you can send them an application request. You’ll then be notified via email if the advertiser you selected has approved your application. If you are approved, the Google affiliate panel will create links for you to use on your website or blog.