So here goes
- If its just a single website with no backups storing stuff to disk then its just a standard WEBSITE not a cloud (Hello Sidekick)
- If its a physical box that is meant to help you manage a virtual environment... then its not a cloud (hello Cloudburst appliance)
- Seriously if you are just a single website doing stuff with a database you aren't a cloud (hello Soonr)
- No seriously if about buying a physical box it isn't a cloud (like HP's spin though that they are just cloud enabling... nice weasel room)
And I could go on. The point is that cloud is an infrastructure thing, it is IaaS in the "aaS" hierarchy. PaaS can have a go at being cloud but SaaS is "just" something that might be deployed to a cloud. Having a website (SaaS solution) that runs on Amazon doesn't make that SaaS solution "a cloud" it makes it a SaaS solution hosted on a cloud.
The hardware point is that making capital expenditure is exactly what a cloud isn't about and physicality is exactly what a cloud isn't about. You want virtual compute and storage that you pay as a utility. This is the economic model of cloud.
So in the words of Kryton. I know that strictly speaking I've only identified two things, but they were such big things I thought I'd say them twice.