Electronic commerce consists of the buying and selling of products or services over electronic systems such as the Internet and other computer networks. It is more than just buying and selling products online. It also includes the entire online process of Developing, marketing, selling, delivering, servicing and paying for products and services.. For example, you may think of Amazon, which provides online shopping for various product categories, such as books, music, and electronics. This form of e-commerce is known as electronic retailing, or e-tailing, and usually involves the transportation of physical items. It is also referred to as business-to-customer, or B2C. E-commerce types represent a range of various schemas of transactions which are distinguished according to their participants.

•Business-to-Business (B2B)

•Business-to-Consumer (B2C)

•Business-to-Employee (B2E)

•Business-to-Government (B2G) (also known as Business to Administration or B2A)

•Business-to-Machines (B2M)

•Business-to-Manager (B2M)

•Consumer-to-Business (C2B)

•Consumer-to-Consumer (С2C)

•Citizen-to-Government (also known as Consumer-to-Administration or C2A)

•Government-to-Business (G2B)

•Government-to-Citizen (G2C)

•Government-to-Employee (G2E)

•Government-to-Government (G2G)

•Manager-to-Consumer (M2C)

•Peer-to-Peer (P2P) Software that accommodates a B2C scenario generally consists of two components:

1. Store Front: The website that is accessed by customers, enabling them to purchase goods over the Internet. Data from the store catalog is typically maintained in a database, and pages requiring this data are generated dynamically.

2. Administration Console: A password-protected area that is accessed over a secure connection by store staff for purposes of online management. This typically involves CRUD (create read update delete) access to the store catalog, management of discounts, shipping and payment options, and review of customer orders.

More info http://en.wikipedia.org/wiki/Electronic_commerce