Hook to other services, such as DNS-o-matic or Cisco Umbrella/OpenDNS

As per subject - those would be very useful!
Thanks a lot in advance for considering them.

Do you mean these services should update your dynv6 zone, or the other way round?

I mean the other way around - I would like to have “hooks” like I have for TunnelBroker. When I update a service with Dynv6, other dynamic DNS providers could be updated automatically - similarly to what DNS-o-matic does - unfortunately DNS-o-matic is not very reliable and does not support Dynv6 (although I asked).
Actually just supporting DNS-o-matic would allow you to automatically support all of their services.

I’ve just added support for updating external services via the dyndns2 protocol:

By using a dyndns2 hook you can send your updates to DNS-o-matic or to any other services supporting this protocol.