Why do we use the term "Bandwidth" on the Net?

I originally learned the term "bandwidth" from radio.  This is the width of
frequency used on any given carrier signal.

In other words, if you're listening to the Philosophy Radio Station, WYMI
on the AM "Band" at for example, 690KHz, there is "bandwidth" depending on
the strength of the signal anywhere between 688.xxKHz to 691.xxKHz.

This is why you would start hearing WYMI before your tuning knob reaches
"69" on the dial.

On the FM "Band" where you have a wider frequency per carrier signal.  They
used modulate the signal along portions along the width of the signal.
 This achieved the result of being able to carry on several conversations
at once using the same transmitter.  Depending on how it was modulated, (my
memory is reaching to about 20 years ago) and the width of the frequency,
you could get from 4 to 16 channels on the same radio wave.  Some were used
for teletypes, some for voice.  In those days, anyone who used more that
one channel at a time for the same or cross purposes, or used government
frequencies to call their girlfriend,  "wasted bandwidth".

So why do we use that term now?  All signals are sent serially one bit at a
time.  No "bandwidth" is wasted, except in the last example, where only
"time" on the circuit is being wasted, not the width of the band.  To
achieve a similar result on a digital circuit, for example a T1, the same
single user PC computer would have to be sending data to multiple
recipients along different channels on the T1 at the same time.  (This has
been possible on the larger computers, and of course with the advent of
Windows 95, this could be possible with multitasking, and multiple I/O
cards, don't know about MACS.)

(And of course, I'm sure some portions of the 'net use satellite and
microwave comms, and "bandwidth" really does come into play.)

Cc:  HPUX-L; HP3000-L