“The Cloud” is a popular term in the tech world and much like a cloud it doesn’t have a clear definition. People have personal clouds, companies have clouds, and the Internet is a cloud by itself. So what is a “cloud?”
Think of a cloud in the sky. While it looks solid from the ground, everyone knows that clouds can be passed through. Clouds are made of trillions and trillions of water drops all floating in the air together. A small cloud can become part of a big cloud and a big cloud can be separated into small clouds.
The Internet is much the same way. Each internet device is like a droplet of water. Devices in a computer cloud can pass information between each other. The broadest set of devices that can pass information back and forth is called the Internet. But if you set up a personal cloud, that means you are defining a specific set of devices that can access specific information. People can make a cloud of any size, and a single device can connect to many clouds.
When people say that they back something up to “the cloud” or host something on “the cloud,” they aren’t all referring to the same cloud – what they mean is that there is a network of computers that they can send their information to. Because these computers all store the same information, if one droplet falls out of the cloud, nothing is lost. Computers in a cloud can be spread all over the world; what matters is that a number of computers have an agreement to share certain amount of information with a specific number of people.
Source: Nerds On Call