So far, there have been no official moves to usage-based pricing in the U.S., but (of course), AT&T has been experimenting. Rogers in Canada has been using the model since 2008.
It appears that the ISPs, most of which are cable TV providers, as well, are scared of the exponentially growing usage of web video spurred by Netflix, Hulu, Amazon, Apple and more recently HBO and Google.
Time Warner, the second-largest US cable operator, says they lost 126,000 pay-TV accounts last quarter as more consumers "cut the chord."
The ISP tried to test tiered pricing in 2009 but overwhelming consumer disgust forced the company to drop the attempt.
Streaming services such as Netflix have vocally panned the move, which will force it (and other similar companies) to lose millions of subscribers.
Just so everyone knows, I didn't add it to the article but ISP margins on broadband range from 92-99 percent. Yep.