If your network cannot handle the traffic, don't offer the services. In network access for the masses, downstream bandwidth has always been easier to deliver than upstream. It's been that way since modem manufacturers found they could leverage a single digital/analog conversion in the PTSN to deliver 56kbps downstream data rates over
Mikael Abrahamsson wrote: phone lines. This is still true today in nearly every residential access technology: DSL, Cable, Wireless (mobile 3G / EVDO), and Satellite all have asymmetrical upstream/downstream data rates, with downstream being favored in some cases by a ratio of 20:1. Of that group, only DSL doesn't have a common upstream bottleneck between the subscriber and head-end. For each of the other broadband technologies, the overall user experience will continue to diminish as the number of subscribers saturating their upstream network path grows. Transmission technology issues aside, how do you create enough network capacity for a technology that is designed to use every last bit of transport capacity available? P2P more closely resembles denial of service traffic patterns than "standard" Internet traffic.
The long term solution is of course to make sure that you can handle the traffic that the customer wants to send (because that's what they can control), perhaps by charging for it by some scheme that involves not offering flat-fee. I agree with the differential billing proposal. There are definitely two sides to the coin when it comes to Internet access available to most of the US; on one side the open and unrestricted access allows for the growth of new ideas and services no matter how unrealistic (ie, unicast IP TV for the masses), but on the other side sets up a "tragedy of the commons" situation where there is no incentive _not_ to abuse the "unlimited" network resources. Even with as insanely cheap as web hosting has become, people are still electing to use P2P for content distribution over $4/mo hosting accounts because it's "cheaper"; the higher network costs in P2P distribution go ignored because the end user never sees them. The problem in converting to a usage-based billing system is that there's a huge potential to simultaneously lose both market share and public perception of your brand. I'm sure every broadband provider would love to go to a system of usage-based billing, but none of them wants to be the first.
-Eric