The API for Cloud 1.0 is the virtual machine/OS. The API for Cloud 2.0 is the application container itself – services like CloudFoundry, from Amazon and Heroku allow a developer to hand over an application to the application container without having to know anything about what operating system that application is running on or how it communicates with other services like load balancing, failover and database.

via PaaS Is a Cloaking Layer for Clouds | SYS-CON MEDIA.