This is an excellent organisation tool.  To me it is far better than the standard "tree list" based GTD (Get Things Done) Applications.

The main point of success are:

1) Being able to fold and unfold, giving you the ability to see only what you are currently working / focused on.

2) Great for linking everything together on your computer (e.g. websites, people (email address links), Word documents, Excel spreadsheet) - I even have a link to a script on my Mac which performs an automated backup of all my important files, I just click the button and I end up getting an email telling me of what was backed up.

3) Very fast to develop a map.  I mapped out all the projects I'm working on in one evening, and it's already made my life easier today, I can now focus on what I'm supposed to be doing.  If I come up with a new unrelated idea halfway through, I can just add it to the correct place on the map, and continue with what I'm supposed to be doing.  I no longer write an idea down on a post-it and end up losing the post-it, and then the idea.

4) It's fun.

IMPROVEMENTS:
One improvement is to be able to add your own 16x16 icons (or whatever they are), and assign your own names to them.  The icons are not necessarily compatible with everyone's projects or maps - this is really limiting.  I end up either not using them at all, or just use the obvious ones, like the phone and email address, plus some priority digits, and ticks and crosses.  The rest I believe are fairly redundant for me.

Many thanks to the people involved :o) :o)