hmmm - whilst sharing is defiantly one of the first and easiest use-cases to envisage, there are a whole host of other API's that will be built on this includin

hmmm - whilst sharing is defiantly one of the first and easiest use-cases to envisage, there are a whole host of other API's that will be built on this including registration for authentication (via OpenID - only present the services the user uses), cloud-based file pickers, print, send, bookmark, and in the future a lot of system generated events. The point isn't that this is an unnecessarily generic API - it is not, it is like saying postMessage is a unnecessarily generic API, rather it is firstly a service discovery mechanism and simple communication channel.