Hypertext and Knowledge Management: personal history
In earlier history, some wealthy people had their own personal libraries to store and organize knowledge. Now the tools are better and usually support close to free access to information.
As good as graphical user interfaces are for browsing the web, examining links between data sources, etc., I still think that the "killer application" for knowledge management will have a simple (mostly) text interface that uses natural language understanding and (in a semantic web sort of way) be able to search on content based on meaning.
As an aside: my top priority research project that I am scheduling about half my time for in December and early next year is to add "RDF generation from plain text" to my KBtextmaster system. I will post a link when I have a white paper ready on how I plan on doing this.