Steve Ballmer said it quite right: Android was a bet on the technology of the past (OS, installable apps, etc), and Chrome OS is a bet on the future (webapps, light clients, etc.)
technology of the past (OS, installable apps, etc)
Except it turns out that obsolete stuff like local storage and direct hardware access and being able to run offline is actually sort of useful, which is why everybody is falling over themselves trying to jam all of it into HTML5.
