I'm still trying to get to grips with the mental model of a dokuwiki. Wikis sit somewhere in the middle of the continuum of information spaces: on one end, nested structures with a very visible hierarchy: to such documents we are conditioned both through print media and traditional online texts. (I write “to such documents” on purpose, to distinguish between nested documents that rely on conditional and sequential relationships, and looser agglomerations of documents.) On the other end of the continuum, distributed documents with only tags or other meta-data to identify them, and accessible essentially through search results.
Dokuwiki plays it both ways: namespaces allow the building of hierarchical structure in documents, while the open links between documents make the structure optional and decidedly not the only way into the texts.
So far I've failed to get the “tag” plugin to work…