Using this feature, it is now possible to for example have different noise-profiles for different parts of a curve, which makes it possible to do animate camera shake for example. Or perhaps, for having greater control of mixing and matching different parts of F-Modifier effects, such as combining several generator modifiers to get multi-case functions for instance. See http://aligorith.blogspot.com/2011/06/gsoc11-fmodifier-range- masks.html for details.