Great question from Glyn Moody at Slashdot:
The response to Google’s Chromium OS has been rather lukewarm. But suppose it’s just part of something much bigger: a netbook computer from Google that would cost absolutely nothing. Because all the apps and data are stored in the cloud, storage requirements would be minimal; screens are getting cheaper, and the emphasis on lean code means that a low-cost processor could be used. Those relatively small hardware costs could then be covered by advertising in the apps — after all, they are just Web pages. Interestingly, Google has not only rolled out advertising to more of its services recently, it has also started running AdSense ads in the desktop application Google Earth. Would you accept a free Google netbook — or is the price you would pay in terms of the company knowing even more about what you do on an hour-by-hour basis just too high?
(Plenty of links in the original.)