This is kinda neat. It is an access solution for those who are away from their home machines for long periods as well as an expansion of networking capabilities on the local network. MS calls it "Peer to Peer" networking and I was almost refreshed to see them name something descriptively, instead of trying to invent some cool catchword for it.
You won't be seeing this very soon, but you will be seeing it. It is simply too clever to ignore. Existing home and enterprise equipment has only spotty support for IPv6, the next generation Internet Protocol. That will change with time and once the necessary hardware is in place.
Microsoft's detailed outlay of how it works is here.