Mary Jo Foley asks : “Is Windows Vista … the last big-bang release of Windows.”

At a Convergence conference yesterday, Microsoft CEO Steve Ballmer had no doubt. A questioner asked him : “With all the hoopla here at the conference around SharePoint Server, is it correct to think of SharePoint as almost like an operating system?”

“Microsoft officials increasingly are talking up ‘Software + Services’, as opposed to ‘Software as a Service’ in explaining Microsoft’s future. So how does Microsoft keep the growing family of business services it is introducing tethered to on-premise software?”

SharePoint Server is the obvious answer, avers Foley. No, not Windows. And not Windows Server either. Not even Office. But simply SharePoint.

Ballmer answered the questioner in positive terms :

“SharePoint is the definitive OS or platform for the middle tier.” It is the “missing link”, Foley explains, “between personal productivity and line-of-business applications”.

“SharePoint is just like Office; it’s a bunch of point products gathered together into a suite. Although Microsoft is not fond of calling out the six or so servers that comprise Office SharePoint Server, it is a bunch of server apps loosely joined.”

Microsoft is currently experimenting with making SharePoint Server “the new, must-have platform for its business users. Microsoft Business Solutions (MBS) is the captive laboratory for Microsoft’s Software + Services experiments.”

How will that affect the consumer end of the market, we wonder?