Scaling the UV map of the cube does not make the texture appear larger or smaller, nor does changing the Scale on the mapping node. (Changing the scale seems to drag and stretch the texture off to one side, high values make it disappear completely)
My confusion is not helped by the fact that it appears differently in Textured, Material, and Rendered views.
In Textured view, Scaling the UV map does change the size of the texture:
However, it looks completely different in Material view:
Could someone explain how the mapping node should be operated?