[_mhr_]

I've always thought that ZUIs would be confusing for users. It's a completely modal interface. If you can zoom in infinitely or zoom out infinitely, it would probably be hard to determine where you are conceptually. Can anyone address this?

[varl]

I imagine that a minimap could help with that, or showing nearest neighbors at the edges of the viewport, and perhaps being able to alt-tab between applications as well as groups would help.

You can use space to have a visual organisation of things, but you don't have to navigate the space since it's virtual. You should be able to navigate suitable to your platform running the viewport.

Pinch-to-zoom, drag to move, two-finger tap to bring up list of applications to move to instantly on a tablet.

Keyboard based navigation and manipulation of the canvas if you prefer to not use a mouse on your workstation.

Click to drag and scroll-to-zoom to navigate with a mouse, when that is more appropriate, for example.

[andrewflnr]

You tell by looking. This will utilize people's very well-developed pattern matching and spatial memory abilities. That said, it's not too hard to imagine a quick "show me where I am now" overlay, or a breadcrumb type header/footer/sidebar that shows what regions of the desktop your view is zoomed into. This is the opposite of modality: everything relevant is right in front of your face.

If an argument from authority means anything, Jef Raskin, one of the creators of the Archy system mentioned, is a large part of the reason modal UIs are Considered Harmful. If he thought ZUIs were an answer, well, you might have something mixed up.