The document discusses different dimensions and classifications of e-commerce. It describes how e-commerce can be classified based on the degree of digitization as either pure or partial e-commerce. E-commerce is also classified based on transactions and interactions as business-to-business, business-to-consumer, business-to-business-to-consumer, consumer-to-business, consumer-to-consumer, and peer-to-peer. Mobile commerce and location-based commerce are also discussed. Examples of popular e-commerce sites like Amazon, eBay, and Bhinneka are provided and their key features summarized.