People often talk about the "protocol stack" of the internet, moving from transport (lowest) to applications/content (highest). And the idea is that lower layers are not supposed to discriminate against the higher ones. We've been used to the FCC regulating transport, but they're getting into the business of regulating applications -- like VoIP. And companies that provide broadband access would like to be able to discriminate in favor of their own voice and video services, rather than letting all comers ride across their network. So both companies and regulators are cutting across the layers of the protocol stack.