Android is the first free, open source, and fully customizable mobile platform. Android offers a full stack: an operating system, middleware, and key mobile applications. It also contains a rich set of APIs that allows third-party developers to develop great applications.
Across my career, I am most proud of Android—as a platform, as a family of phones, and as a catalyst for change in an otherwise closed industry. But the most exciting part is what's next. Download the SDK and start hacking.