Think about a movie that you're downloading via BitTorrent*. Better yet, visualize it using this amazing BitTorrent visualization. Where is the movie stored? Well, on the hard drive of the person who started the torrent. Except they might have left the swarm by now. So instead, on the hard drives of a couple dozen other users. Except none of the ones you're talking to may actually have a full copy of the movie, just the pieces of it you happen to need.
Instead, stop looking at the nodes. They come and go, none of them are vital. Instead, look at the center of the simulation: the mass of bits flying from one node to the next. That's where the movie is. This is the cloud: the real cloud, not the marketing term. The movie isn't on a device, it's on the network, perpetually in transit, stored in the very wires and routers that compose it. And as long as enough nodes exist to bounce it around, it will stay there. Already, there are some torrents that have stayed alive for over seven years, almost from the birth of the protocol. And as the size of the online population increases, the volume of data stored in the real cloud will increase.
Search engines like The Pirate Bay, currently used mostly for purposes of dubious legality, will become the first guides to this new, amorphous universe of disembodied content. Content independent of storage, independent of source, stored in the body of the network itself. No vendor can rent this cloud to you by the hour, nobody can buy it or sell it or control it at all. That's part of its power. That's part of why the real cloud is so very different from the way data has existed before. You don't decide what gets stored on the real cloud: the cloud does, in the ultimate participative democracy. All you can do is feed new things to the cloud and hope it likes it, and provide new tools for getting data in and out.
This is a big deal. It is a phase-change in the nature of data, from liquid to gas. We are only just beginning to see and understand the implications of this transition. Serious research into the real cloud, and tools built around it and on it, are being stunted by the association torrents have with illegal behaviour. But that's going to fade. If you're looking for a blue-ocean field of emerging technology, where you can do new, exciting things and make a big difference, look at the real cloud.
* which you obviously don't do, since you use BitTorrent only to legally download free Linux distributions. So imagine a hypothetical movie.