Google AdSense: Google AdSense provides anyone with the opportunity to feature ads on their website, blog, or search engine. Once viewers click the ads featured on your site, Google will pay you a portion of the revenue they received from the advertiser. There is no set amount that you will be paid because each ad clicked will make you a different amount of money. To understand why each ad is worth a different amount, check out the companion article Google AdWords.

       Due to the nature of the AdSense business, Google has strict policies and regulations regarding the content of your site. You cannot place AdSense on any site that violates any of these conditions:

* Violent content, racial intolerance, or advocacy against any individual, group, or organization

* Pornography, adult, or mature content

* Hacking/cracking content

* Illicit drugs and drug paraphernalia

* Excessive profanity

* Gambling or casino-related content

* Excessive, repetitive, or irrelevant keywords in the content or code of web pages

* Deceptive or manipulative content or construction to improve your site's search engine ranking, e.g., your site's PageRank

* Sales or promotion of weapons or ammunition (e.g., firearms, fighting knives, stun guns)

* Sales or promotion of beer or hard alcohol

* Sales or promotion of tobacco or tobacco-related products

* Sales or promotion of prescription drugs

* Sales or promotion of products that are replicas or imitations of designer goods

* Sales or distribution of term papers or student essays

* Any other content that is illegal, promotes illegal activity, or infringes on the legal rights of others

       In addition to regulating your content, Google will not tolerate false clicks of the ads they put on your site. If you engage in "click fraud", Google will terminate business with your site. So, no, you cannot sit down with your friends and click on ads all day to make yourself money. Your account may show a balance of hundreds of dollars from your clicks but I guarantee you that Google will never pay you! Market your site and get real visitors from across the world to generate much more money then you ever could by clicking ads yourself! Once you reach $100.00 in your AdSense account, you will be eligible to receive your first payment from Google. Before paying you, they will thoroughly review your site’s content and the clicks that came from your ads. If they find you guilty of "click fraud", they will refuse payment. I have heard from plenty of "savvy" webmasters within dollars of payout who got kicked out of AdSense for violating Google’s policies. Don’t be lazy! If you keep your business practices legitimate, AdSense will provide you with a nice revenue stream. The money you make is not free imaginary money. Somebody paid to put ads on your site! This program is made possible by Google’s other advertising operation, AdWords. In AdWords, companies pay a set amount per click of their ad. If someone clicks an ad from your website, Google will give you a portion of the amount that the advertiser paid it for the click.

More is explained on AdWords here!