The San Antonio-Express News had an article titled In a test, Time Warner Net hogs will pay for bytes. The basic idea is that people downloading movies use up lots of bandwidth and that slows down things for the rest of us that use the internet for more basic purposes. Since they are slowing things down, maybe they should pay more. So if they do this less (which would follow the law of demand), then things would go faster for the rest of us. Some experts say that more broadband infrastructure could take care of the problem.
But these big downloaders might be creating what we call negative externalities. Some people impose costs on others like drivers who create pollution. One solution to that is to tax the polluting activity. This higher price on the movie downloaders is like a tax.
This is also like paying a toll on highways. When few people are on the highways, you don't need tolls. But if things get congested, one way to unclog them is to charge a toll. I had a blog entry on this a couple of months ago. You can read that here.