The document discusses the history and principles of web GIS using Esri products. It describes how Esri has evolved its web GIS capabilities from early desktop-based systems to modern web services-based approaches using REST and SOAP. Key aspects covered include Esri's ArcGIS Server for publishing map, geodata, and other services; the REST and SOAP APIs for accessing these services; and examples of web and mobile applications built with Esri's JavaScript, Flex, Silverlight, and mobile SDKs.