Does powdered whey protein go bad?

I have a 1/4 tub of vinilla whey protein powder left that I bough quite some time ago. I get just about all my protein from "real" sources so it's kind of old since I don't use it much. It says "best by Feb, 2007" on it. I looks, smells and seemingly tastes fine. Does this stuffy go bad? I've got some strawberries and bananas that I'd love to throw into a blender with it tomorrow morning but I'm hesitant since it is well over two years past the "best by" date.