Zoomable Tree (a quicker way to navigate a tree)

I've got a reason for not posting for the last few days. I've been busy. Last friday I was trying to figure out a better way to navigate a tree. I had an idea. I did some mockups. Now I've got a working javascript example (thanks to Prototype, Scriptaculous, and my new favorite text editor: TextMate). I'm pretty happy with how it turned out.

I am also very open to ideas of how to improve the concept, code, or anything else.

Need more input. Before I spend another boatload of time perfecting this and making it compatible with IE, I would like to know if it is a good idea. So I've created a useable example for y'all to try out.

Click here to see it in action
Note that this does not work in Internet Explorer yet.