Business email, calendar, documents and intranet sites for your company – Google Apps for Business.

I wonder what the difference is between this form of application hosting and internal application hosting on a server. When you install Exchange on a local server Microsoft handles the configuration of the machine, and the basic requirements. Moving to the cloud is thus about what we choose the application to manage (in the cloud then the application manages the whole hardware stack – on the server it manages just the releavant resources)…

My question is thus is SaaS cloud computing or not?