This is incredible. I think Google is doing a great job of transitioning from a startup to a big company. They have so many things like this, 20% time, and letting tech guys focus on tech and still get promotions. I feel like they are trying to make themselves the Mecca for brilliant technologists. If you aren't a startup with an "us" against the world mentality, you have to add compelling reasons to attract talent.
transitioning? they've had over 20,000 employees for a few years now. you cease to be a startup after you've started up. for them that probably happened around 1998-2000.