UI Thoughts
One of the central ideas in Jef Raskin‘s book The Humane Interface is that the “zooming” interface — rather than 2d windows that you shift around and overlay on each other, you have a huge canvas that you can zoom into and out of, as well as move around on. Obviously your screen only displays a small portion of that canvas at any one time. A further implication is that you have a “document centric” model, and thus that your data is always visible, and you just start editing it rather than starting an app to view/modify it.
That has pretty heavy implications, and renders most existing software simply unsuitable for a “ZUI”. So while there’s a couple of attempts at implementing them, they’re nowhere near being generally usable. Still, they’re a cool idea.
The thing I like most about them (in theory) is that you can get a broad, 2d overview of everything you’re doing, then zoom in on a bit and work on that. I hate trying to work out how to organise myself in the file system, because I always leave crap lying around where it ends up getting in the way later.
But if you’re willing to compromise a bit, it’s probably possible to fake this. If you consider the “project view” to be whatever you can see on the screen (after using Exposé to get rid of overlapping windows maybe), then a ZUI is just a matter of being able to see many project views at once, possibly scaled, move amongst them, and zoom into one and make it functional. There no great need for zoomed out projects to be functional — you can’t see what you’re typing anyway.
That’s not impossible. If you have two modes: “zoomed out” for navigation, and “zoomed fully in” for manipulation, then the latter is obviously implemented by just having running apps, and the former can be implemented by: (a) taking a snapshot of the apps; (b) closing them; (c) embedding the snapshot in a larger canvas, along with other snapshots; (d) allowing you to navigate around the canvas; (e) when a snapshot is selected, restarting all the apps in the same state as when they were closed. (a), (c) and (d) are just graphics manipulation, and are trivial. (b) alone is trivial; (b) and (e) combined are something KDE and Gnome at least have been doing with session management for ages.
A real ZUI would let you drag components from one section of the canvas to another, too. And let you scale running apps so you can get an overall idea of what they’re displaying but not worry about them taking up much screen space. And a zillion other things too.