This document defines and provides examples of the main types of e-commerce: - Business-to-business (B2B) involves sales between businesses, such as a manufacturer selling to a retailer. - Business-to-consumer (B2C) enables direct sales from businesses to consumers through websites. - Consumer-to-business (C2B) has consumers creating value for businesses, like providing product reviews or ideas. - Consumer-to-consumer (C2C) allows individuals to buy and sell directly to each other on sites like eBay.