Cloud is a new concept of networking based on something called as Virtualization. Using this concept of Virtualization to provide different kinds of services to Users, small scale to large scale companies. Image Courtesy from Wiki which is originally by OmniGroup These services are mainly classified into, 1. SaaS -- Software as a Service 2. PaaS -- Platform as a Service 3. IaaS -- Infrastructure as a Service 4. HaaS -- Hardware as a Service Cloud makes any service available online making users access everything that they need with few clicks. To understand better, following is a youtube video from IBM's BlueMix Cloud. You can watch this video and see that its so simple to have your own site created on a server to which you can choose hardware configurations. Enjoy the Video from IBM BlueMix -- CLICK HERE Also refer to Wiki link for more details and History -- Click Here Happy Learning.