Earnings season has so far been mostly kind to IBD 50 stocks, with some of the biggest gains sparked by results that beat the consensus. Business-and-career social networking platform LinkedIn (LNKD) gapped up and screamed 21% Friday in its highest volume since its debut on May 19, 2011. LinkedIn earned 35 cents per share on $303.6 million in revenue, reflecting gains of 192% and 81%, respectively. The results crushed estimates of 19 cents on