From ZDNet:
Microsoft is in the early stages of a plan that will see virtually its entire lineup of underlying Internet services opened up to developers, the software maker made clear this week.
In addition to making available its existing services, such as mail and instant messaging, Microsoft also will create core infrastructure services, such as storage and alerts, that developers can build on top of. It’s a set of capabilities that have been referred to as a “Cloud OS,” though it’s not a term Microsoft likes to use publicly.