Initially, electronic commerce between two companies used a data sharing arrange- ment called electronic data interchange (EDI). EDI enabled computer-to-computer data transfer, usually over private telecommunications lines. Firms used EDI to plan produc- tion, adjust inventory levels, or stock up on raw materials using data from another com- pany’s information system. As B2B volume soared, the development of extensible markup language (XML) enabled company-to-company traffic to migrate to the Internet, which offered standard protocols, universal availability, and low communication costs. XML is a flexible data description language that allows Web-based communication between different hardware and software e nvironments.