E-commerce refers to the buying and selling of goods and services online. It allows sellers to cut costs by not needing a physical store and reach global markets. Key components of e-commerce include placement of products online, secure payment systems, and fulfillment of orders. There are different types of e-commerce transactions including B2B (business to business), B2C (business to consumer), C2C (consumer to consumer), and others. Common applications that support e-commerce are email, enterprise content management systems, instant messaging, and shopping cart software.