One of the biggest fears about cloud implementation /use is security. I agree. So, why you don't use PaaS, SaaS and maintain the data inside your company? Are you afraid of expose ESRI, Oracle, Microsoft or other software packages to the public? Or just your data?
I think more marketing actions as the "Trust ESRI" seen on AGOL blog here need to happen: ArcGIS Online | What's New - July 2014