Cloud Computing is for sale on the corner of the street. It is the ultimate lease concept. Nothing needs to be owned and everything is for rent. Unfortunately, as the occasional Denial-of-Service (DoS) attack already shows, the system will break down long before 60 billion people demand an instantaneous 24/7 service. As meanwhile the number ofWeb-based appliances is exploding, the cloud is clearly getting overcrowded. In an attempt to satisfy this demand, we could easily all get a cloud in the back garden.