Squidview is a program that displays the squid proxy server log file in a nice
fashion, providing the log file is in squid's native reporting fashion. It has
features such as search, report generation, monitor mode and supports three log
files.

Thus, the program can be used to monitor Internet usage on a networked site.
But please note squid has to be running first and this program is not a
proactive resource controller. What it can do is tell you who and which sites
are consuming the most bandwidth.