I think we're going to have to minimize our traffic over established links for such a system to work. Three types of media come to mind -- 1) Open-air (e.g. ra

I think we're going to have to minimize our traffic over established links for such a system to work. Three types of media come to mind -- 1) Open-air (e.g. radio but possibly IR, optical, etc.) 2) Electric lines 3) Water pipes or other forms of conductive media 4) Couriers So far, so good. The trickier problem is how to get people to adopt the new system while keeping out the snoopers or other bad guys.