Capital Expenditure to Operational Expenditure
IaaS, Amazon EC2, Rackspace
PaaS, Application (aPaaS), Force.com, Enabling (ePaaS), Microsoft Azure, Google App engine
SaaS, CRM, SalesForce, Office, Office 365, Google Docs, E-mail, Gmail, Etc..
Fabric, Google App engine
Instance, Amazon EC2
(Public) connections, Bandwidth, Speed, Uptime
Being able to get a copy of all data
Being able to delete all data
For example, shared authentication mechanisms such as OATH help in creating an integrated set of services.
It's often relatively quick and easy to start using a cloud service. As such, there's a real danger for cloud service proliferation within organizations.
Managing 'scale down' just as good as 'scale up'
Energy saving, Less hardware idletime, More efficient cooling in data centers
Virtually unlimited storage
Virtually unlimited computing power
Handle usage peaks more easily
Reduce costs / capital expenditure
Pay per use