Diversus Group explains why it is called "The Cloud".
In the very early days of telecommunications everything was physically connected. Any two end points on the telephone network could be traced through a series of direct physical connections. Drawing these networks was relatively simple. As technology progressed from analogue to digital these direct connections were no longer required. Information exchanged on a call was broken down into discreet digital packets and sent (or routed) between two different addresses on the network. These packets of digital data did not necessarily travel on the same route and may not have arrived in the same order in which they were sent.
Because there was not a fixed permanent connection between the two sides of the connection and because these digital packets could be mingled with other packets from other sessions, these connections were drawn as clouds on network diagrams.
The internet is the ultimate cloud network. Thousands of smaller networks are all interconnected into one single global network. A device or ‘thing’ on one network can connect to a device on another network. “The Cloud” has changed from its original meaning to now refer to the entire internet.
If you have data in “The Cloud”, remember it is just sitting on someone else’s physical computer (albeit, a very big computer) and you can access it from anywhere you can get an internet connection.