[aohtsab]

I've always been confused on this part — do ISPs have a certain bandwidth to start out with, of which they then allocate portions to their customers?

The problem with 'bandwidth-hogs', from that assumption, is that ISPs oversell pieces of their pie based on some equation of how many people use how much.

I've never understood why one can sell "up to 5 Mb/s", and then sanction your customers who used their service to that extent.

It's like dangling a carrot in front of their face and smacking them when they get too close.

[saurik]

Bandwidth over the course of seconds and bandwidth over the course of days are not comparable. If you are using the fast bandwidth provided to download a file and have it nearly instantly, that's great. It is wonderful to be able to watch YouTube videos without buffering, to get entire webpages in the blink of an eye, and to install an OS over the network without wishing you had splurged for the Cd's. But as soon as you provide something like that, you get some asshole who thinks that it is then his right to use that speed /constantly/, doing nothing but downloading files day and night. If everyone does this, there is no more bandwidth to go around: the expectation is that users will use "up to 5MB/s" only for a few seconds, not for days at a time. You might even say a fair allotment of the finite bandwidth resource might be "5MB/s, or 100MB/min, or 1GB/hour", despite those numbers not even remotely multiplying out. And this is, in fact, how many ISP's are now trying to solve the problem of people who don't understand the concept of sharing: "burst rates", where as you use bandwidth it slows down over short time spans.