Earlier quoted context omitted.
> Many of these companies should have had fail-over to competitors at least for reliability. How would you even set such a thing up? I fear that you might get a couple of collusionary companies that bail each other out and smaller providers might just be left out to dry…
Many DNS providers have the ability to do AXFR "zone transfers", so you can sync your records to a secondary provider and you would add a secondary set of nameservers for redundancy. Unfortunately Cloudflare doesn't offer this unless you pay for their Enterprise plan (they started offering it earlier this year). I do love using CloudFlare for DNS, lots of great features and generally works well, but I wish they would…
That's all they did. They weren't a mail host or provider, there was no UI, nothing. All they did was allow you to specify them as, well, a secondary MX, so if you were offline they'd cache your inbound email until you were back. Simple. Efficient.