The document introduces e-commerce by defining it as any business transaction conducted over the Internet. It describes the three main categories of e-commerce as business-to-consumer (B2C), business-to-business (B2B), and consumer-to-consumer (C2C). Examples are provided for each category. The advantages of e-commerce are listed as increased sales, decreased costs, and allowing small businesses global reach. Disadvantages include inability to sell some products online and high capital investment needs.