Google AdSense is one of the easiest ways to make extra money from your website or blog.
You only need to sign up for AdSense account after getting approval you need to copy some code into your site to display the ads, Google automatically start showing relevant ads related to your website/blog content and you earn every time someone clicks on ads showing on your website. You may also earn from impressions in some cases.
All advertisement of Google Adsense is derived from a program called Google AdWords which is (also known as Google PPC).
You often see these ads displayed above the free/organic results and along the right side of the page on Google.com.
These are called Sponsored Results, and the advertisers using Google AdWords are paying a certain amount of money to Google for these ads when their ads get a click.
AdSense is your revenue share from AdWords ads. When someone clicks, you earn approximately 68% (depending on ad type) of the click and Google gets the rest.
Google AdSense is an auction-based system that allows advertisers to compete for those spots on a site. The ad which has the highest bid and most "quality" ad, gets the top spot and so forth.
It's a very popular website and blog monetization program that can help drive additional income to your website, and it's really best for blog and website that are mainly content driven.
The more content you have, the more Google can get a sense for what your site is about and better match the ads to your website and display relevant ads on your site.
Please make sure you read this entire article and also related articles on my blog. very frankly speaking AdSense is not a get-rich-quick scheme and this alone cannot make you rich overnight. it takes a lot of work to make money. Don't think that just because you join Google ad-sense, you are guaranteed to make big money.