How Data Is Transmitted on the Internet
Computers on the Internet are set up as interconnected rings. In the example below, let's say that we are sending data from computer A to computer K. Computer A sends the data to all the computers on its ring--B through F. Computer D is a special kind--a router. It recognizes that the data isn't meant for any of the computers in its ring, and so it sends it one level up, to routers G through I . Router H recognizes that the data is meant for one of its computers, and so sends it around its ring, J through M. Computer K receives it, and everyone is happy. But in sending data from computer A to K, 12 other computers get the data, too. This is why you are constantly warned about sending valuable information on the Internet.
There are some moderating factors, however. Data is not sent in large chunks; it is broken up into small pieces (called "packets"). Two packets going from one computer to another could take very different routes. And the volumes of data streaming through a given computer are very large indeed. If you sent insider-trading secrets to your best friend, the Securities and Exchange Commission would have to do a lot of work, and have a very wide reach, to sift through and reassemble your transmission intact. So don't worry about someone reading all your correspondence. But because a person needs only one wayward credit-card number to do a lot of damage, the danger remains.
