I think this is a good example of how the "cloud" is not a silver bullet to making your site always up. AWS provides a way to keep it up, but it is up to each developer to ensure that they are using AWS in a way to make sure their site can handle problems in one availability zone. I think we will see more of a focus from big users of AWS about focusing on how to create a redundant service using AWS. Or at least I hop…
This outage is affecting all AZ's in the East. So even a multizone setup wouldn't help for this one. Only a multiregion setup. This outage is a lot like having your entire datacenter lose power.
If that is not the case, then having a multi-region setup would be a necessity for any major sites on AWS.
Perhaps there will be a time where to truly be redundant, one would need to use multiple cloud providers. Which would be a _huge_ pain to do now I imagine, with all the provider lock-ins we have.