General Principles
1. There are multiple routes to every destination. Machines select the best routes.
2. All data is sent in packets, along the fastest routes possible. One short e-mail may be split into 3 packets and sent along 3 routes, then re-assembled at the destination machine.
3. Connections between nodes are established only long enough to send packets. They are not held open like phone lines.
4. The technology used is standardized, universal, and free, allowing many different types of machines and programs to communicate with each other.
Who pays for all this?
Nodes pay for their own connections, but can basically use the rest of the network for free.
A rough analogy: If you develop your own suburb, you build your own roads and connect them to local roads. This allows the homeowners to drive from your roads to wherever they want more or less for free. This also allows people who live outside of your suburb to drive into it, also for free. The Internet is like that.
Need to know more?
A good history of the Internet is at http://www.davesite.com/webstation/net-history.shtml
Some interesting geographical maps of Internet nodes are at http://www.geog.ucl.ac.uk/casa/martin/atlas/geographic.html
Introduction
to the
Internet
Jeff Williamson
What can I do on the Internet?