I’m happy to see a post from @swardley about Private versus Public cloud terminology. I’ve never considered the issue settled clearly, so I’m glad to read in Private vs Public clouds:
I thought this argument has been settled a long time ago, seems not. So, once more dear friends I will put on my best impression of a stuck record.
Better to sound like a stuck record than delusional. 
He goes on to note two dimensions of cloud definition: private vs. public, and internal vs. external
First what is the difference between a public and a private cloud?
- A public cloud (the clue is in the name) is open to the public.
- A private cloud (the clue is in the name) is private to some set of people.
…
There is another side to this which is your relationship to the provider. It is either :
- external to you and therefore controlled, operated and run by another party.
- internal to you which means it is controlled, operated and run by yourself.
Unfortunately, this definition seems to be the commonly accepted one. I say “unfortunately” because it fails to recognize an important dimension: connectivity. Let me just accept the terminology here, rather than fight it, and suggest a new term to describe the nature of network connectivity:
- Global – cloud resources are connected (directly or via firewall and/or NAT) to the Internet
- Local – cloud resources are connected to a private network, such as a VPN or other internal network environment
Now, I wouldn’t have picked these terms if I could have just used Public/Private or Internal/External instead. But since people have been stuck on yesterday’s way of thinking, that “Cloud” == “Internet Connected”, the good terms got used to describe control and ownership instead. But it is an important distinction, because a cloud isn’t any good without network connectivity and the nature of that network connectivity defines the baseline audience of users. Further it suggests a security paradigm, QoS domain, etc.
The choice of “global” and “local” mirrors terminology used to describe IP addresses, which might be “globally unique” or “locally unique”. (Of course, most people refer to the latter category as “private”, but I digress…) If you can think of a better term for the dimension of cloud connectivity, please let me know. But whatever you do please don’t forget that the nature of network connectivity is an important distinction for cloud usability, especially in enterprise organizations.
