You may be wasting your free time in front of Facebook, but the social networking leader is laughing all the way to the bank. Its revenues doubled in the first half of 2011 to $1.6 billion, reports Reuters. Net income also grew strongly, reaching $500 million in the first half, up from $350 million in the first nine months of 2010. Thanks in part to the company's popular "Like" button, rates for ad click-throughs jumped 62% between Q4 of 2010 and Q2 of this year. Facebook accounted for one-third of all online display ad impressions in the US in June—more than Google, AOL, Microsoft, and Yahoo combined. (More Facebook stories.)