In principle, a P2P cloud could be built using the ordinary computing, storage, and communication equipment found now in people’s homes, with essentially zero initial investment. Broadband modems, routers, set-top boxes, game consoles, and laptop and desktop PCs could all contribute. The challenge is to turn this motley collection into a coherent and usable cloud infrastructure and offer its services to customers. You also have to ensure that the salient features of clouds—on-demand resource provisioning and the metering of service—are maintained.
This would surely be tough to do, but think of the advantages. First, there would be no single entity that owns or controls it. As with most other P2P applications, a P2P cloud could be created and operated as a grassroots effort, without requiring the permission or consent of any authority. People would choose to participate in a P2P cloud by installing the appropriate client software on their local machines, and the value of the resulting cloud infrastructure would be commensurate with the number of individuals who are contributing to it.