Wikis for documentation make sense for many reasons, including low cost of implementation, ease of publishing, and collaboration possibilities. DITA has become a popular XML format for semantic markup of information and is generally used for documentation. Wiki content is generally authored or stored as wikitext, which is an non-standardized markup format. Should DITA be used as a markup format for wikis instead of wikitext or HTML? I believe the answer is that DITA in the authoring environment of wikis is impractical and does not work for general audiences.
I work at IBM where DITA was first invented and where we author an unimagineable amount of content in DITA. We create all kinds of tools to support its authoring, transformation, translation, specialization, and delivery. DITA has in various capacities been explored as a format for a variety of delivery mechanisms, including content management systems, wikis, microformatted XHTML that retains DITA markup, and also your more standard outputs. Basically, if some tool or application is out there, we’ve likely tried to make it DITA friendly.
Know your audience
You must know your audience to create quality documentation that meets the requirements of the user. Most of my users are database administrators and application developers. My guess is that none of the users of the products I work on knows a thing about DITA markup. DITA requires some upfront education for anyone that is going to create content in the desired manner.
A core feature of a wiki is the collaborative editing and authoring aspect. By using DITA as the wiki markup, you are removing that feature by subjecting your potential authors to learning a new language and all its nuances. The word wiki in Hawaiin means quick. Quick also implies easy.
Subjecting one of our users to DITA authoring would be a significant hindrance in terms of their ease in offering contributions. Public collaboration on most documentation projects is extremely difficult. Tom Johnson in his article on A Few Surprises in using a Wiki for Documentation discovered that most contributors were likely to only make small edits rather than add to the documentation set. Why throw another roadblock in the way?
Most people author their content visually to create the desired elements and effects. When they want emphasis on a term they will use bold or italics. They won’t want to consider should that emphasized text be a UIControl, parmname, apiname, varname, or one of the many other semantic tags–they will use the non-semantic bold tag.
Do you try to hide the complexity of authoring in DITA from users that do not care and just want to write? Do you create a kind of hybrid DITA wiki that features some of the benefits of both worlds? Is a light-weight CMS really a better solution for easy authoring? Maybe a DITA to WordPress import plugin or to Drupal or Joomla?
Currently, I don’t feel there is a good answer for the human element of DITA and wikis. I responded to Tom Johnson’s blog post when it was first posted stating that I believe there is common ground between wikis and DITA but most of that common ground is in terms of technical implementation rather than usage patterns.
I am not saying there is not a place for a native DITA wiki, but the use case is probably for collaboration among DITA authors rather than with a larger community of end users.