What? Nobody felt like doing some research?

There's a company out of Sweden that has offered software that does this same thing for years now, only they don't try and offer up some nebulous "Unlimited" quantity that will be buried down in the terms of use somewhere.

Look up a program called Wuala, Not only have they actually given a 45 minute presentation at Google explaining how their p2p file storage and sharing system works, but they've also shown how they secure their files /and/ how they make sure that you won't lose data.

While the possibility of robot armies is a truly frightening one, it's the same for any other new technology. Tech is really the only thing that ever changes, so I feel confident that good or bad, new tech makes the world a better place.