Salt cloud is a public cloud provisioning tool. Salt cloud is made to integrate Salt into cloud providers in a clean way so that minions on public cloud systems can be quickly and easily modeled and provisioned.
Salt cloud allows for cloud based minions to be managed via virtual machine maps and profiles. This means that individual cloud VMs can be created, or large groups of cloud VMs can be created at once or managed.
Virtual machines created with Salt cloud install salt on the target virtual machine and assign it to the specified master. This means that virtual machines can be provisioned and then potentially never logged into.
While Salt Cloud has been made to work with Salt, it is also a generic cloud management platform and can be used to manage non Salt centric clouds.