A well written document should focus the reader. When everything is a hyperlink and a "thought map" then you'll just end up being distracted and either not read

A well written document should focus the reader. When everything is a hyperlink and a "thought map" then you'll just end up being distracted and either not reading the original doc, or clicking on nothing and ignoring the deluge of hyperlinks. The demos in this article are heavily obstructed by all the visual noise. If something is important enough, the author will discuss it directly in the document. Hyperlinks can provide context when the reader may not have the context assumed of the intended audience, or they're a poor man's bibliographic citation (because the links always break eventually), but otherwise it's a signal that it's _not_ important.