http://www.rei.com/product/688268/rocky ... TAodcWoqnA
I know alot of hikers use these because they don't want to deal with gore-tex runners that keep water in. i think the general thought is to wear them over your socks. Think of taking a goretex boot/shoe but having it be modular. You can put on the goretex socks when necessary. I haven't used these myself, but I have used plastic grocery bags over my socks in a pinch and they worked really well to keep my feet dry in sodden shoes. Try searching through threads on backpackinglight.com, thats where I heard about them.