Exactly - was it the case that ALL cogent traffic being blocked - from everything that I've read, it was. Cogent's circuits were just overloaded. They had sold transit to Netflix that they were unable to provide.
Netflix customers, in this situation, can point their fingers at Netflix (who, in turn, can point them at Cogent).
If Cogent provided 1 Gigabit of transit to Netflix, but didn't have circuits with which to connect Netflix to their customers, well, It will be interesting to see what kind of Liquidated Damages Netflix wrote into their contract with Cogent. Maybe it will be enough to pay their peering fees with Comcast.