E-commerce is buying and selling using an electronic medium. It is accepting credit and payments over the net, doing banking transactions using the Internet, selling commodities or information using the World Wide Web and so on.
E-Business in addition to encompassing E-commerce includes both front and back-office applications that form the engine for modern E-commerce. E-business is not just about E-commerce transactions; it's about re-defining old business models, with the aid of technology to maximize customer value. E-Business is the overall strategy and E-commerce is an extremely important facet of E-Business.
Thus e-business involves not merely setting up the company website and being able to accept credit card payments or being able to sell products or services on time. It involves fundamental re-structuring and streamlining of the business using technology by implementing enterprise resource planning (ERP) systems, supply chain management, customer relationship management, data ware housing, data marts, data mining, etc.