Three features that separate "the cloud" from hosting

There are three features that separate "the cloud" from previous notions of outsourced hosting or managed services:
- Multi-tenancy: You contract for a service, not a physical server. Your application may share hardware and other resources with other customers without any impact on the service level you receive.
- Elasticity: You can configure new services in minutes. The providers have large enough scale to be ready with excess capacity, and have created management panels that allow for self-service provisioning.
- Location independence: Your services can be moved quickly to other data centers in order to provide increased capacity, uptime, and/or disaster assurance. The "cloud" is a whole new paradigm made possible by advances in virtual server management.