Before considering cloud-based data protection, it is important to first understand the basics of cloud, which can sometimes be foggy (at best). With trade magazines and publications defining the "cloud" in a number of different ways, IT managers and executives are often confused about the true meaning of the term; however the recent maturation of cloud-based services has helped the definition become more focused.
In a nutshell, there are two main types of cloud-based data protection services: public and private. The public cloud is where data is on a shared infrastructure. In a private cloud, data is on dedicated infrastructure and the owners of that data share no part of it with others. There are variations of the public and private cloud, including combinations of the two that result in a "semi-private cloud," but for the sake of clarity, we will stay away from that topic.