Professionals used to flock to LinkedIn ( just to share their résumés with colleagues -- as well as possible future employers. But the online social business network, which went public in 2011, now offers its more than 200 million users posts from the likes of Arianna Huffington, Richard Branson, and Barack Obama, who write on topics of their choosing. (Board members persuaded several of their powerful friends to join LinkedIn's Influencers platform.) The initiatives created greater value, which boosted engagement. Revenues, the bulk of which come from the company's recruiting tools, increased 86% in 2012, topping off at $972.3 million. )
Wal-Mart retook the top spot, Berkshire Hathaway made the top five, and Apple grew enormously.