What is a good strategy to keep my site online when S3 goes offline? What is a good strategy to keep my site online when S3 goes offline?

If S3 US East 1 goes offline, how should I have my app configured/structured to prevent that taking my entire site offline?

What are the best strategies to diversify in this sort of situation?
In March 2015, Amazon AWS announced they support S3 replication across regions. When a certain region in S3 goes offline, you can serve files from your mirror in another region.

source: https://aws.amazon.com/blogs/aws/new-cross-region-replication-for-amazon-s3/

The practice of keeping your infrastructure online by doing a switch over to another region is a complex one, but S3 is a relatively small and simple component. Netflix has a great article on their experience with Chaos Gorilla.

This also applies to service degradation, like increased latency. Not just when a service you depend upon is completely offline. Netflix has an article on this as well: Chaos Engineering Upgraded.