A type of business model, or segment of a larger business model, that enables a firm or individual to conduct business over an electronic network, typically the internet. Electronic commerce operates in all four of the major market segments: business to business, business to consumer, consumer to consumer and consumer to business. Also sometimes written as "e-commerce" or "eCommerce". Ecommerce has allowed firms to establish a market presence, or to enhance an already larger market position, by allowing for a cheaper and more efficient distribution chain for their products or services. One example of a firm having successfully used ecommerce is Borders. This book store not only has physical stores, but also has an online store where the customer can buy books, CDs and DVDs.