However, most people familiar with the situation are taking any Comcast statement with a grain of salt right now. For one thing, despite their rhetoric, Comcast has refused to say exactly what form the "network management" that apparently manages to stop much BitTorrent traffic actually takes. Even FCC Chairman Kevin Martin expressed doubt over Comcast's claims, noting in an appearance last week at the Consumer Electronics Show, "When they have reasonable network practices, they should disclose those and make those public."
In reality, what Comcast is being accused of isn't exactly "blocking" applications. Rather, the claims are that they're delaying packets used for particular applications, most notably BitTorrent, for a period of time that will cause them to time out waiting to be delivered. In other words transfers will be stopped because Comcast's network engineers delay them. Although this may not technically amount to "blocking" an application, in effect that's exactly what's happening.
Certainly the eyes of other ISPs and various online service providers of different types will be watching to see the outcome. Besides dealing with the specifics of the Comcast situation, the FCC has also been asked by Vuze Inc, a company that (legally) distributes content using BitTorrent, to clarify the exact rights and responsibilities ISPs have to allow or deny particular traffic. According to some, the 2005 FCC rules mandate that as long as content isn't illegal to begin with, ISPs have no right to treat it any differently than the rest of their network's traffic. Comcast, on the other hand, has said that they feel their "network management" is within the FCC guidelines.
Source: Ars Technica