I started a wishlist for a user experience on a web site that could feature traditional content you would find on a web site but with a user interface displaying hierarchy and navigation like a mindmap. One such app is MindMeister.
Get a free account on MindMeister just to start exploring its features.
One cool feature of MindMeister that I have not seen anywhere else.
When you add a link to a topic and you choose URL as the category a suggested list of links appears as the results from a google search. You avoid the inconvenience of navigating to a different browser tab just to do the search outside of MindMeister.