<h1> Darwin Information Typing Architecture</h1>
'Topic' - The highest standard structure in DITA. Topics are not nested. (Example: A topic within a topic)
: <b>Section</b> - Used for internal organization of a Topic, these define or directly support the topic
: <b>Processing Context</b> - Any higher structure than a topic used to handle context. (*Examples:* Print-organizing structure or the helpset-like navigation)
: <b>Reuse</b> - Two Levels
:: <b>Topic reuse or Course Grain Reuse</b> - Because of the non-nesting structure of topics, a topic can be reused in any topic-like context. :: <b>Content reuse or Fine Grain Reuse</b> - Via a _conref_ attribute that can point to any other equivalent element in the same or any other topic.
: <b>[http://www-128.ibm.com/developerworks/xml/library/x-dita2/index.html Specialization]</b>. Allows any DITA element to be extended into a new element whose identifier gets added to the class attribute through its DTD. Therefore, a new element is always associated to its base, or to any element in its specialization sequence.
:: <b>Topic specialization</b> - A way to extend the generic topic into new information types (or _infotypes_). (Example, a recipe, a material safety data sheet, and an encyclopedia article are all potential derivations from a common reference topic).
::: <b>NOTE</b> By default, DITA has three specialized topic types: _Concept_, _task_, and _reference_. :::: <html><img src=“http://www-128.ibm.com/developerworks/xml/library/x-dita2/basediag.gif”/>
:: <b>Domain specialization</b> - The element vocabulary within a topic (or set of infotyped topics) can be extended by introducing elements that reflect a particular information domain served by those topics. (Example a specialized domain, such as programming phrases, can be introduced by substitution anywhere that the root elements are allowed.
:[http://thecontentwrangler.com/article/10_dita_lessons_learned/ 10 Lessons Learned Moving to DITA]
:[http://thecontentwrangler.com/site/moving_to_dita_lessons_learned_from_mark_lewis_of_hyperwriters/ Lessons Learned Moving to DITA Article]
:[http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=285881&intsrc=article_pots_side Computer World Introduction Article]