Вот картинка хорошая, показывает как именно деплоятся разные типы клауда.
Русское описание с wikipedia мутновато, imho.
Вот англ. вариант:
Цитата:
Deployment models
Public cloud
A public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet. Public cloud services may be free or offered on a pay-per-usage model.
Private cloud
Private cloud is infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally.
They have attracted criticism because users "still have to buy, build, and manage them" and thus do not benefit from lower up-front capital costs and less hands-on management, essentially "lacking the economic model that makes cloud computing such an intriguing concept".