Outliner-based web browsing idea

This extremely cool idea came up as a feature request on the Marginnote forums. It was basically a wish to be able to use the app as a browser, but in Mind Map mode (or outline mode). I thought some people here might find it interesting or inspirational.

A screencap of the idea is pasted below:

I think the Firefox plogin Tree Style Tabs pretty much gives you this… I live by it (doesn’t help me control the number of tabs I have open :-))