References

1. https://www.icann.org/news/announcement-2016-06-01-en
2. But they can be delegated to new nameservers at any time
3. Key Relay Mapping for the Extensible Provisioning Protocol
4. "Hidden primary" means a nameserver from which all other authoritative nameservers load their data, but it is never published in the nameserver delegation for the zone and thus does not receive actual queries from the internet.

5. One logical master, you can still design for high availability at that master level via clustering and mirroring
6. http://luadns.com and http://dns-api.com to name a couple
7. Zone Poisoning: The How and Where of Non-Secure DNS Dynamic Updates http://mkorczynski.com/ IMC16Korczynski.pdf
8. Because of this, I frequently point out to people that by geo-targeting their URL forward instead, which is comparably trivial to do compared to full-on GeoDNS, you probably get more accuracy...