Paradise

Revenue model is description of how the company or an E-commerce project will earn revenue. It is include 5 models such as sales revenue model, transaction fees model, subscription fees, advertising fees, advertising model, and affiliate model.

Sales revenue model is companies generate revenue from selling merchandise on their web site of from providing a service
Transaction fees is company receives a commission based on the volume of transaction made.
Subscription fees are customers pay fixed amount, usually monthly, to get some type of service. Fee from subscribers is in exchange for access to content or service.
Advertising fees is companies charge others for allowing them to place a banner on their sites.
Affiliate fees are companies receive commissions for referring customers to other Web sites.

Now, let me compare each revenue model for Google, eBay, and Amazon.com.

Sales Revenue Model: The main representative is Amazon.com
The major revenue of Amazon.com is selling book, CDs, DVDs, software and so on. Amazon.com reported over 1.3million sellers sold products through Amazon’s worldwide web sites in 2009. Not only Amazon.com, eBay also make revenue through sales revenue model as well. However, Google seldom involve in such model as it major business is search engine.

Transaction Fees model: eBay is classical example for this model.
eBay is platform let people buy and sell their goods through their website. It become the intermediate in this trade and received transactions fee between them. Amazon.com and Google not much this kind revenue compare with eBay.

Subscription Fees Model: These three companies all got this kind of model.
(1) eBay
(2) Amazon.com
(3) Google

Advertising Fees Model: it is Google major revenue source.
Almost 99% sources revenue of Google is advertising fees, such Google Adwards and Google Adsense

Clickriver Ads can place advertisement on the Amazon.com

Same as the Amazon.com, eBay also got some this kind of model.

Affiliate Fees Model: Pay-Per-Click is most popular that Google use it generates revenue. As compare with eBay and Amazon, Google also very famous in this. Nowadays, affiliate program is also become more popular compare with advertising as it also part of the advertising. eBay and Amazon trend to become most using it as well..

References:
www.eBay.com
www.Amazon.com
www.Google.com