I would have thought that of all the things that are a bit confusing about UI, that the idea of a canvas wouldn't be one of them.

Think workspaces, or the extended desktop metaphor used in many desktop OSes. Except they are *stitched* together as one whole. Because the resolution and physical size of the sum of these stitched screens is greater than that of the device, you begin to pan through each.

Depending on the implementation, it could be smooth or not - that's up to the UI design from that end. Ideally, it should be going in one direction (left to right/right to left or top to bottom/bottom to top). But that can be something that the UI frameworks of Maemo 6 leaves to the users to stitch together.

*throwing this in there
Imagine that you had this canvas, and by holding a function button and doing a gesture with the device that you could move between those parts of the canvas. Imagine what that does for creativity and productivity applications. Also, with the fact that you have a greater resolution being used - for the canvas as a whole - imagine what you could pump out via a TV-Out/HDMI-Out facility. Imagine how that device can now be useful for traditional computing tasks, but when its physically in a mobile context, it submits to that end as well.

This is what's possible, now