i think it's just higher quality textures in general, otherwise it's called ambient occlusion ^^
"In computer graphics, ambient occlusion attempts to approximate the way light radiates in real life, especially off what are normally considered non-reflective surfaces.
Unlike local methods like Phong shading, ambient occlusion is a global method, meaning the illumination at each point is a function of other geometry in the scene. However, it is a very crude approximation to full global illumination. The soft appearance achieved by ambient occlusion alone is similar to the way an object appears on an overcast day."
http://www.interstation3d.com/tutori...s/dirt_map.jpg