Tagging documents

Structured document formats like DITA, DocBook, and Solbook are characterized by deeply nested tags and a multitude of schema constraints.
Unstructured tagging languages like HTML, on the other hand, are wide open.
Some people think that it is a contest between the two types:
Read the summary [more..]
OR the full article:
blogs.sun.com/.../do_we_really_need_structured.
The answer may lie in the correct choice of tagging for particular information. More uses information should mean more structure to that information (and more tags). More information and more users of the information should also mean more structure.