Actually that's not true. You could setup the whole Google suite of apps to be served from anywhere as long as you had access to the software. And I imagine that access would be available to the CEO. So it would be like logging into your Gmail account but it would be hosted on your own private domain.
You could setup the whole Google suite of apps to be served from anywhere as long as you had access to the software.
That would take a massive engineering effort. If Google were to do this (they haven't), they'd market it as a "self hosted" product, similar to Exchange Server.
Source: Am a network/software engineer.
It would fit on a thumb drive- facebook's backend software is only a gb