Topic-oriented writing is a disciplined approach to writing that emphasizes modularity and reuse of concise units of information: topics. Well-designed DITA topics can be reused in many contexts, as long as writers are careful to avoid unnecessary transitional text.
Conciseness and appropriateness
Readers who are trying to learn or do something quickly appreciate information that is written in a structure that is easy to follow and contains only the information needed to complete that task or grasp a fact. Recipes, encyclopedia entries, car repair procedures--all serve up a uniquely focused unit of information. The topic contains everything required by the reader.
A well-designed topic is reusable in other contexts to the extent that it is context free, meaning that it can be inserted into a new document without revision of its content. A context-free topic avoids transitional text. Phrases like "As we considered earlier ..." or "Now that you have completed the initial step ..." make little sense if a topic is reused in a new context in which the relationships are different or no longer exist. A well-designed topic reads appropriately in any new context because the text does not refer the reader outside the topic.
Most print publications or web pages are a mixture of content and navigation. Internal links lead a reader through a sequence of choices as he or she navigates through a website. DITA supports the separation of navigation from content by assembling independent topics into DITA maps. Nonetheless, writers may want to provide links within a topic to additional topics or external resources. DITA does not prohibit such linking within individual topics. The DITA relationship table enables links between topics and to external content. Since it is defined in the DITA map, it is managed independently of the topic content.
Links in the content are best used for cross-references within a topic. Links from within a topic to additional topics or external resources should be avoided because they limit the reusability of the topic. To link from a term or keyword to its definition, use the DITA keyref facility to avoid creating topic-to-topic dependencies that are difficult to maintain. See Key-based addressing.