Why LinkedIn is best of the class of 2011 By: MarketWatch February 14, 2012 at 00:00 AM EST LinkedIn’s secret sauce is not such a secret, as it is the same as Facebook’s: Each social network gets data from its users for free, writes John Shinal. Read More >> Related Stocks: Google, Inc. Groupon Cl A Pandora Media Inc Zynga Inc Cl A