Acceptable Use Policy (AUP), 
which basically restricts use of the NSFNET Internet "backbone" to 
research, academic, and government uses. It expressly forbids commercial activity unrelated to research.
The AUP doesn't apply, however, to the fastest-growing segments of 
the Internet run by commercial Internet service providers like 
PSI, 
UUNET, and 
Netcom.  In 1990, these providers formed a non-profit 
organization, the 
Commercial Internet Exchange (CIX), that is dedicated to carrying commercial Internet traffic.
Q.	What's USENET?