Look, I don't think it's necessarily technically feasible for every ISP right now to do the kind of blocking that is already proposed. There was no description in the FairPlay application of what site blocking is. We hear a fair amount about DNS blocking, so if that's what blocking is at this stage.... You know, DNS is fairly common for ISPs to provide, but it wouldn't necessarily be required. Presumably, an ISP might configure all of its users' systems to go to a DNS server and then not have to maintain a DNS server. There's no requirement to provide a DNS server, so presumably that ISP wouldn't be able to block it. If there were a requirement to block it, I guess that would require putting a DNS server in place, making their end-users use it—I'm not sure that's a possibility—and blocking it.
So, that's just sort of the simplest case.