Maya Lighting & Rendering 2: Mental Ray Part 9 - Ambient Occlusion
This tutorial showed 3 different methods of using Ambient Occlusion within a scene. Method 2 you could use an Area Light to have Ambient Occlusion affect all of the objects in the scene without dragging them into onto each shader/texture like in Method 1. I didn't know this and I find it useful because that can take quite a long time if there are a lot of different shaders and textures. However, I prefer Method 3 because in the past I found this gave me the greatest amount of control over how much I wanted Ambient Occlusion to influence my renders.