At an early stage of development of a network when still very few people thought of a semantic marking, sites represented assemblies of pages. Pages were either completely static, or interactivities somehow animated for giving. The general(common) method for advertising sites was their positioning as special "places" - the Network as the virtual world with the shops and portals.

At the end of 90, and approach of XML-technologies and webs - services is especial in the beginning of 21-st century began to change gradually design and the device of sites. XML-technologies have allowed the information to become the general(common) and accessible to various systems, and webs - services have provided interfaces to "interiors" of sites. Thus, the visual interface for a data access has turned in program (API).

Quite good examples of webs - services - sites eBay and Amazon. Their database is accessible to each programmer who in forces to write the interface for job with API.