Reservations in the US are a special class of enclave, which means a sovereign nation that physically exists inside another country. Other examples include Lesotho (contained within South Africa) or Vatican City (contained within Italy). What doesn't exist, and what I have a hard time imagining, is this sort of "distributed enclave" that's been suggested - an entity that exists in multiple places, each of which is within a different sovereign entity. It seems like a flimsy arrangement. Who's to stop any one country from taking over "internet territory" within their borders?