The method used to move data around on the Internet. In packet switching,all the data coming out of a machine is broken up into chunks, each chunk has the address of where it came from and where it is going. This enables chunks of data from many different sources to co-mingle on the same lines, and be sorted and directed along different routes by special machines along the way. This way many people can use the same lines at the same time.

You might think of several caravans of trucks all using the same road system to carry materials.