This tension became evident in a recent HipChat interview where HipChat, makers of an AWS based SaaS chat product, were busy creating an on-premises version of their product that could operate behind the firewall in enterprise datacenters. This is consistent with other products from Atlassian in that they do offer hosted services as well as installable services, but it is also an indication of customer concerns over privacy and security.
Read more at: http://highscalability.com/blog/2014/1/8/under-snowdens-light-software-architecture-choices-become-mu.html