Syco - Sounds like something they have heard / made up and as stories go on they change along the way. A Lot of ISP have gone now to the model where everyone gets 2mbit (or as fast as your line will take) on ADSL and the difference in price is the usage per month - so a LITE User gets say 3 GIG month and pays £14.99 where as a heavy user might pay £29.99 for example.
Doofy - To answer your question, there is a few ways you can look at this - a Person with one connection but a few people using it - such as a family might well clock up a big D/L a month say even though they are not doing anything Illegal. The other side of the coin is you can get stuff via News Servers (NTL Provide one with content) and P2P which then also starts clocking your Uploads as well. You asked though what the hell they are downloading to hit 600GIG month (and maybe were are they storing this?) well Movies, Games, MP3, general useage and probably leaving it downloading 24/7. Games are getting bigger (DVD in Size), with increased speeds you can also grab DVD Un-Compressed (well not DivX Anyhow) etc etc etc.
The best idea I saw for Caps was a rather simple model - 1am - 8am not counted...but pointless talking about how and why anyhooo, NTL (and ISP's) will carry on doing whatever it is they want to do
