The Associated Press reports that Comcast appears to be blocking some peer-to-peer traffic. Specifically, they appear to be forging reset packets on upload traffic for protocols such as BitTorrent. This is a very dangerous trend and needs to be stopped.
The central question is who determines what runs on the Internet, end system owners or ISPs. Traditionally, the Internet has fostered the "smart host, dumb network" model, and it has succeeded brilliantly. Rather than innovation being controlled by a small number of providers — and for consumers, at least, the economics favor local monopolies or duopolies — the smart host model draws on many small entrepreneurs and technologists from around the world.
Is copyright the issue? BitTorrent is partnering with content owners, including Fox, Paramount, Warner Bros. and MGM. Besides, Comcast is not a law enforcement agency. This isn’t a simple semantic complaint; when one is dealing with the legal process, there are guarantees of due process and an opportunity to contest the charges.
They may be concerned about bandwidth consumption. This is a legitimate concern, especially since the technology of cable ISPs makes upstream bandwidth more expensive. In that case, though, the remedies are first, to tell customers — per the AP story, Comcast is not saying precisely what its policy is — and second, to use traffic-shaping rather than simply sending resets. Traffic shaping addresses the real problem (overconsumption of expensive upstream bandwidth) without choking innovation.