Google wants to enable Google applications to run as well as possible as many places as possible. Here is how:
Google applications: Web applications run in browsers, on all kinds of systems. No need to be installed or updated, and hard to block. Anyone with IE, Firefox, Safari, Opera, or, of course, Chrome has access to all the latest applications.
Gears: Web applications run in a sandbox and don't have much access to your system. Gears enables more access. Applications are still in a sandbox, but the Gears-enabled sandbox is bigger, and can persist. This frees Web applications from having to be connected all the time.
Chrome Frame: Chrome Frame puts the Chrome browser inside Internet Explorer. This shows the lengths Google will go to in order to give Google applications the best possible runtime environment is as many situations as possible.
Android: Android is a Linux-based OS for mobile handsets and other devices. Android has exploded in popularity among handset manufacturers. This is Google's first win in computing platforms, and Google influences the software “stack” all the way down to the hardware. Android has a Webkit-derived browser.
Chrome OS: Chrome OS is meant for things larger than handsets. Chrome will be Google's attempt to bring a Linux-based OS and Web-based applications to netbooks and PCs.
Google's strategy is comprehensive: Control the software all the way down to the hardware where possible, and, if that isn't possible, be compatible, and maximize capabilities, on every possible platform.
Google's strategy is also technologically coherent: Java, Linux, Webkit, SQLite, Eclipse, and other common components are reused across multiple Google products and platforms. You can expect Google to contribute to and influence the development of these key ingredients. You can also see some design philosophy in common across Google products. For example, Android runs Java applications in multiple tasks, and Chrome runs Web pages/apps in multiple tasks to make these systems resilient to apps that crash.
While Google's applications, like Gmail, are proprietary, Android, Chrome, Gears, GWT and many other components of Google's strategy are open source software, many with permissive licensing that would not preclude competitors from using them. Open source builds confidence in Google's partners and in software developers using Google platforms.
Google's strategy has formed recently and moved quickly. It can be hard to perceive the impact. As fast as Google is implementing this strategy, you can expect a similarly fast emergence of an application ecosystem around Google's strategy. This will be one of the most significant developments in software in the coming years.