What are the differences between public and private clouds?

There are grossly two cloud service models, viz., public cloud and private cloud. They have different sets of costs and benefits. The public cloud service model is probably what many people would consider the archetypal model of cloud computing. In the public cloud model, a provider sells cloud services to multiple unrelated clients, or tenants. They leave back end maintenance and operations to the cloud computing provider. This arrangement is very cost effective, and lets clients rest easy knowing that the security of their information assets is in good hands. A private cloud can be operated by the same organization that uses it, or a dedicated provider can operate the cloud on the organization’s behalf. A private cloud, when managed properly, is the most secure type of cloud service model because it is directly controlled by its client. Private clouds also make more efficient use of physical IT assets than traditional data centers, but are lesser economically beneficial than outsourced cloud service.
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