I've used NS quite a bit for travel. I've gotten rides/driven people from here, stayed on a few couches, had people stay on mine... Even in France I found an NSer to let me sleep at his place for 3 days during If3.
I pretty much plan to travel around in Europe for a Month next winter by staying at NS'ers places and skiing with them. I've already gotten 2 invites + 2 other people I have actually met because of NS. So I'm now at 4 of at least 7 places I want to stay during my travels.
before the whole olympics thing, I was considering getting the mountain collective pass and doing something like this. Maybe next year.