Topic-based authoring
A topic is a discreet piece of content that is about a specific subject, has an identifiable purpose, and can stand alone (does not need to be presented in context for the end-user to make sense of the content). Topics are also reusable. They can, when constructed properly (without reliance on other content for its meaning), be reused in any context anywhere needed.
Topic-based authoring is a modular content creation approach (popular in the technical publications and documentation arenas) that supports XML content reuse, content management, and makes the dynamic assembly of personalized information possible.
The Darwin Information Typing Architecture (DITA) is a standard designed to help authors create topic-based content. The standard is managed by the [Organization for the Advancement of Structured Information Standards] (OASIS) DITA Technical Committee.