Google is a major player in the online advertising industry. Every time you search Google, you will see ads displayed along with your results. Those ads are never "mixed in" with the results - there is no "pay to play" on Google which is one of the reasons Google became the most popular search engine in the first place. But the sponsored text-link ads above and to the right of the results generate a great deal of money for Google. These ads are known as "Google Adwords." Those who wish to advertise via Google can learn more on Google's Adwords page.
Google AdWords is a pay per click advertising program of Google designed that allow the advertisers to present advertisements to people at the instant the people are looking for information related to what the advertiser has to offer.
By using Pay-Per-Click (PPC) is the best way to send immediate, targeted traffic to your website. It is an online advertising payment model in which payment is based on qualifying click-through. An advertiser has to pay every time his ad receives a click. The Advertisers decide the keywords relevant to their offer that should display their ad and the maximum amount they are willing to pay per click for that keyword.
As for http://www.amazon.com/, it is a well known E-Commerce nowadays. From a sellers books and CDs musical product to a multi seller which include electronics, homes, grocery and many more. The main revenue from amazon is that it sell it product online. Besides that, amazon.com allowed others to published their advertisement in their website. By charging certain commision from the advertiser, it become one of the revenue beside selling their product.
Finally, http://www.ebay.com/ are slightly different from amazon where it dont have their own product to sell. ebay is like a middle person where the website allowed others to post their product on the site and sells them. Transaction fees will be received from those who interested to post their product using the name of ebay. If the product was successfully sold, yet another commision will be received.
When a user searches Google’s search engine, ads for relevant words are shown as "sponsored link" on the right side of the screen, and sometimes above the main search results. Google generate most of the revenue from Google AdWords.
