Growing net book market is what both MS and Google are targeting with their new operating systems. Both companies believe in their projections that this opportunity will grow significantly in the nearest time. Even now few can imagine what they can do with a computer without Internet.
MS is ahead but Google seems to be in better shape for a long race. Google controls a big part of Internet and it makes it easy to enter the market. So, MS brand and popularity will not be such a big deal. Google will also open codes of their system. They believe it will help closing the gap in number of software solutions available for their system pretty fast.
Besides Microsoft has an advantage on this market Google can singnificantly undermine their position on the market of OS for mobile Internet devices.
Anyways, it's going to be a triller. End users will inevitably win from this competition.