January 02, 2012, 12:51:27 pm
"Diffuse shadow" slider: This affects ambient occlusion in areas that are not in the shade.
"Ambient shadows" slider: This affects ambient occlusion in areas that are in the shade.
They haven't changed the wording in the Movie effects yet - I added this to the bug tracker list some time ago, so I hope they can fix it soon.
In other words, SSAO has been renamed to Ambient in the Weather section but they haven't yet gotten round to renaming the SSAO movie effects.