Major types of e-commerce can be categorized:
Business to- Consumer (B2C)
This only focuses on the retail or sale side of the ecommerce. It is commerce between companies and consumers, involves customers gathering information; purchasing physical goods like books or travel or information goods like downloadable digitized material content, such as software, music or EBooks. As an example from in B2C field is Amazon.com mall.
When ecommerce is extended to supply chain management between and among businesses, we get a new concept, which is called Business to business (B2B). In other words, this is strictly business between two or more companies. It focuses more on procurement of physical spare parts or intellectual materials.
This commerce involves direct sales of items from a consumer to another. Item could be fairly used or new. Examples of C2C ecommerce are: Auctions portals, such as eBay, which allows online real-time bidding on items being sold in the Web; Peer-to-peer systems, such as the Napster model where private individual share files containing different kind of data. The Nigerian Jiji.ng is also a good example of a peer-to-peer system of C2C ecommerce.
This involve commerce between businesses and the government of a country. In practise it means the use of the Internet for licensing procedures, public procurement, and other government-related operations. In B2G the public sector has a leading role for establishing e-commerce.
Mobile commerce (m-commerce): Mobile commerce or m-commerce is defined as a process of buying and selling of goods or services through wireless technology.