What is the Internet you might ask?  

The Internet is a collection of networks that are all interconnected.  This
interconnection means that messages from one system on one network can be
sent to another system on another network.  All E-Mail on these networks use
the same format, thus allowing seamless movement of mail within these
networks.  The major players in the Internet are the Research Organisations.
The government pays a fair amount of the cost of the Internet through grants
to these organisations.  Service Providers offer their own networks that
connect up with the Internet at some system within their network.


What is USENET?

USENET is a series of electronic conferences that are distributed to every
system that subscribes to each of them.  Distribution is based on a
'flooding' technique, where any new messages are sent to neighbour systems
that subscribe to that conference, until all systems receive those messages.
USENET currently has over 2,000 conferences that  occupy over 50
megabytes of storage per day.


Here's some good reading tips:

Managing UUCP and USENET
     O'Reily & Associates, Inc., Tim O'Reilly and grace Todino

Using UUCP and USENET
     O'Reily & Associates, Inc., Grace Todino and Dale Dougherty

The Whole Internet: User's Guide & Catalog
     O'Reily & Associates, Inc., Ed Krol

!%@:: A Directory of Electronic Mail Addressing & Networks
     O'Reily & Associates, Inc., Donnalyn Frey & Rick Adams

The Matrix: Computer Networks and Conferencing Systems Woldwide
     Digital Press, John S. Quarterman

Unix Communications
     The Waite Group, Bart Anderson, Barry Costales, and Harry Henderson

Zen and the Art of the Internet.
     Brendan Kehoe, zen-internet.src or zen.txt