[Zaim3]

ChromeOS/Chrome Web Store seems to be about countering the the trend towards "appification" (the consumption of the web through native clients) by turning the web itself into an app store and giving websites native abilities.

Android is Google's take on the appification model. While there's overlap in that Android has a Chrome browser, I think the distinction is that Android's interaction model means that native apps will be primary method for navigation for the forseeable future since the native Web app model doesn't translate cleanly on a touchscreen device.

The Web is essentially Google's Desktop OS, so it has a vested interest in keeping it alive. ChromeOS is a way of accelerating that process, since the closer it gets to becoming viable alternative to an OS running native apps, the closer the web gets by extension. Creating a standalone OS allows them to frame the problem better than just Chrome browser, since a host OS always has a slight masking effect, even if the observer is aware of it.