The Five Characteristics
What actually makes something cloud, instead of just hosted infrastructure.
Plenty of things get called "cloud" that really aren't. These five traits are what the industry actually means by the word.
Provision resources with a click. No human gatekeepers, available 24/7.
Access everything over the internet, from anywhere.
Physical hardware is shared across customers, with dedicated isolation available when needed.
Scale up for traffic spikes and back down when idle, automatically.
Measured Service, the fifth characteristic, is the one that changes how you think about cost: you pay for what you actually consume, not for capacity you pre-purchased and hope to use.
On-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. If a platform is missing most of these, it's hosted infrastructure wearing a cloud label.