All documents are displayed as previews. You can zoom and scroll around the world to find what you want. You can set the size of each document's preview individually, allowing you to make important objects larger (to more easily find them) and less important objects smaller (to get them out of the way.) You don't explicitly deal with file and folder names, but work directly with the content itself. All of the zoom/scroll operations involve trackpad gestures similar to those used on iPhone devices.
Apple has used some of these concepts in their apps (like iPhoto and Aperture), but this is the first example I've seen of it being applied system-wide.