Site developers systematically build whatever infrastructure is requisite to support the functionality required for the retail Web site they are developing. Using good programming principles, they strive for code modularity and re-use. They strive to create a Web site that retains as much flexibility for future modifications as is practical. Where necessary and practical, they develop tools for their own use, the use of Web site administrators, and business managers, although these needs are usually secondary to the creation of the Web site itself.
The vast majority of existing retail Web sites have been created from scratch. When these development efforts began, the e-commerce software packages that are now available were either still under development, or their early versions lacked sufficient functionality to prompt wide adoption. This means that thousands of developers have been duplicating effort over the past several years, building and re-building retail Web site infrastructure that performs essentially the same functions.
Most developers would prefer to use existing, proven infrastructure, and free themselves to work on the functionality that can truly distinguish one retail Web site from another.