Google's Chrome OS is more evidence that Google aims to become the new walled garden of the Internet, a la America Online. For a long time, AOL was a destination where subscribers to its connectivity services became targets for ads, enriching the company twice - once when they paid for their dial-up service, and again when they responded to pitches on the AOL home screen.
Chrome OS follows what is now Google's standard three-fold strategy: offer something that is (1) really good, (2) free, and makes it (3) dead easy to access Google's services. The Chrome browser, Android OS, and now Chrome OS are examples.
No one is forced to use Google's products or, using them, to use Google's applications and services. Like Microsoft, which triumphed for a while by placing its browser icon on the desktop, Google plans to win by being the most convenient option. People like being coddled, even if it means they're being herded into Google's pastures.
Like Microsoft, too, Google will no doubt be surprised when the antitrust vultures swoop in to punish it for for treating customers so well they don't want to patronize anyone else. So it goes.