In the "A .NET developer's view of Windows 8 app development" session at BUILD, the lecturer mentions that only the client-side WCF features are exposed in the Metro profile, we cannot create a server. ( http://channel9.msdn.com/Events/BUILD/BUILD2011/TOOL-930C?format=progressive @ ~34:00)
Does this mean that direct peer to peer communication is not possible for Metro applications, and any data exchanged between 2 users over the internet will always have to actually travel through a non-metro-style application?
Access to sockets is controlled by the "Internet (Client & Server)" capability, if this capability is enabled in your application, you should be able to send and receive data over the internet.
Since the Metro style apps can't run on background, and are designed to be used fregmentedly, making it P2P enabled makes little sense.
来源：https://stackoverflow.com/questions/7507155/no-p2p-in-windows-metro-applications