If only IRC would have been built with multi-server setups in mind, that forward messages between servers, and continues to work if a single - or even a set - of servers would go down, just resulting in a netsplit...Oh wait, it was!

My bet is, FB will reach out to others in FAMANG, and an interest group will form maintaining such an emergency infrastructure comm network. Basically a network for network engineers. Because media (and shareholders) will soon ask Microsoft and Google what their plans for such situations are. I'm very glad FB is not in the cloud business...