Many great resources are available to
explain the mechanics and syntax of specializing the standard DITA DTDs
for your content—for example, Michael Priestley's Specializing topic types in DITA and Eliot Kimber's DITA specialization.
However, I didn't see any that walk readers through the process of
reviewing their existing content, evaluating its fit with the various
DITA topic types, and then designing and building a DITA specialization
around the needs and structure of their content, so I wrote the IBM
developerWorks tutorial DITA topic specializatio

Making the best decision for your documentation needs should be based on business considerations, not just the appeal of XML-based Content Management. XML is exciting; DITA is the hottest technique to use for Content Management, but is it really what you need in your documentation? Steve Wiseman of WritePoint took all of what Alex Masycheff said and turned it on its head.

...One interesting SOA trend that has emerged outside of the traditional application development domain is the service orientation of content—transforming monolithic documents into topic-oriented chunks that can be composed to create new documents and deliverables. DITA was conceived as a model for improving the reuse of content assets by turning them into well defined topic-oriented components.