The value of startups for the broader economy is that they inject innovation and drive dynamism in markets (especially in high tech).  That said, it’s always fascinating to see companies make the transition from nimble, irreverent, fearless startup to the defensive posture of an old stalwart.  This is happening to Google—the ultimate representative of “Valley” culture, and more-and-more its antagonist appears to be Facebook—the new representative of the irreverent, innovative tech startup.  For more on the growing rivalry between Google and Facebook—where Google has become increasingly reactive to Facebook, see today’s article by Caroline McCarthy of Cnet: Google vs. Facebook: Drawing the battle lines  Is it healthy for a company to settle into “reactive” mode in response to emerging competitors?