I do know what he is talking about (I believe that in Safari on a Mac laptop, Ctrl-two-fingers up on the touchpad accesses it directly), but the quality of the scaling is horrible. It is larger, but also more pixelated, edges are jaggy...
Just to complete the Safari story, I'll report that on the Windows version "Zoom" is found in the "Window" menu, while the "View" menu has "Make text bigger", "Make text normal size", and "Make text smaller". These last three seem to do exactly what they say: they change the size of text while leaving images completely unchanged.
As for "Zoom", I'm not quite sure what the Apple folks have in mind. On my (Vista 32) system, when I choose "Zoom" while Safari is taking the whole screen, it chops the window to a little more than half width and slightly less than full height, but text and images do not change size at all (scroll bars appear). If I click "Zoom" again, the width adds a tiny amount, but the scaling doesn't change. After that, additional "Zooms" have no effect whatever. Pretty weird!
Opera has a nice scale-the-whole-content feature which you can evoke using the "+" and "-" keys on the numeric keyboard (doesn't work when focus is on a field looking for keyboard input), and numeric-keyboard-"*" takes you back to normal scale.
The scaling business seems to be so very much different browser to browser that I would never depend on it.