Types of E-Commerce

There are many types of E-Commerce currently but it can be broken into four main categories:

• B2B (Business-to-Business)
  Companies doing business with each other such as manufacturers selling to distributors and wholesalers selling to retailers.
  
  
• B2C (Business-to-Consumer)
  Businesses selling to the general public typically through catalogs utilizing shopping cart software.
  
  
• C2B (Consumer-to-Business)
  A consumer posts his project with a set budget online and within hours companies review the consumer's requirements and bid on the project. The consumer reviews the bids and selects the company that will complete the project.
  
  
• C2C (Consumer-to-Consumer)
  There are many sites offering free classifieds, auctions, and forums where individuals can buy and sell thanks to online payment systems like PayPal where people can send and receive money online with ease.
  
  

Companies using internal networks to offer their employees products and services online (not necessarily online on the Web) are categorized as B2E (Business-to-Employee) E-Commerce.

G2G (Government-to-Government), G2E (Government-to-Employee), G2B (Government-to-Business), B2G (Business-to-Government), G2C (Government-to-Citizen), C2G (Citizen-to-Government) are other forms of E-Commerce that involve transactions with the government which ranges from procurement to filing taxes to business registrations to renewing licenses.

Reference:

http://www.digitsmith.com/ecommerce-definition.html