Org-mode can export to the excellent FreeMind mindmap maker, which exports to a huge number of formats; here’s the export menu:

?freemindmenu.png

The power of this is that you can use Org-mode’s intuitive and simple syntax to export to navigable maps that can then be shared online. Here’s an example of the simple markup:

  ,* Major modes
  ,** Org-mode
  ,** Markdown mode
  ,** php-mode
  ,** python.el
  ,** python-mode.el
  ,* Applications
  ,** Gnus
  ,*** bbdb
  ,** ERC

Click here to see the foldable, clickable export.

I intend to use this for Philosophy revision next year.