Gmail has started rolling out its snappy new interface to the world. This is the same new look which was leaked last week.
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Many won’t see it as default but you would see a ‘Switch to a new look’ link at the bottom-right of Gmail, click to start using the new look and feel of Gmail.
http://www.youtube.com/watch?v=vfW5e6jVsMs
Read more about the new Gmail look here.
Along with Gmail, Google has also changed a lot about Google Reader, read about that here.