Except that HTML/SGML is a format invented for authoring and delivering semistructured text. At the risk of sounding arrogant, the idea is to have domain expert

Except that HTML/SGML is a format invented for authoring and delivering semistructured text. At the risk of sounding arrogant, the idea is to have domain experts (rather than programmers) create stand-alone documents that can then be rendered and type-checked, can be refined by web developers using text macros, page boilerplate, transformations/stylesheets, and script, and that can (but don't have to be) used for rendering dynamic content from markup or other sources such as services and/or databases, while remaining self-standing, autonomous, type-checkable documents in a larger workflow.