Microsoft has remained tight-lipped on the project they call "Midori" beyond confirming that it is an incubation project within the company, but some new details have emerged recently indicating it is a stripped down and modular OS that centers around the net.
According to a report by the SDTimes based on alleged internal documents, Midori will focus on concurrency, where computing resources can be either local or in the Internet cloud and processing tasks can be split among multiple processors and multiple machines. There has been plenty of speculation about Midori going to eventually replace Windows (perhaps one or two generations beyond Windows 7), but Microsoft hasn't even confirmed whether it will actually be a commercial product or not. It seems more likely, though, that its features will trickle down into Windows and be implemented to further integrate the OS into the cloud.