Content reuse in DITA is a fundamental concept that facilitates the management and maintenance of documentation by enabling the sharing of content across multiple documents. At its core, content reuse in DITA involves the creation of modular and granular components of content that can be referenced and reused in various contexts, reducing redundancy and ensuring consistency. DITA allows for content reuse through mechanisms like maps, topics, key-based referencing, and conditional referencing.

A DITA map is a container that references various topics or content modules. This modular approach ensures that changes made to one topic automatically propagate to all instances where that topic is referenced, reducing the risk of outdated information and facilitating version control. By creating a map of references rather than direct reproduction of content, the risk of incorrectly duplicated content is all but eliminated.

DITA topics are standalone content units that address specific subjects or information. They can be authored independently and then referenced or included in maps or other topics. This separation of content into topics promotes reusability as these topics can be reused across different documents and contexts. Topics also regulate and standardize information formatting and styles to ensure that all similar content is constructed in a similar manner.

Key-based referencing is another vital mechanism for content reuse in DITA. Keys are used to identify and reference specific content fragments or topics within a document or across documents. By defining keys and key references, content creators can link to existing topics, enabling the reuse of content without duplicating it. This approach significantly reduces redundancy and ensures that changes to the source content are reflected wherever it is referenced.

Conditional referencing, or conref, allows content creators to include or reference content based on specific conditions or criteria. This dynamic referencing ensures that content adapts to various scenarios, making it a powerful tool for creating variant documents for different audiences or purposes.