Mason is the world's newest billionaire CEO thanks to the successful November IPO of Groupon, the discount shopping site that he founded in 2008. Groupon's path to its public offering
was anything but smooth, and some investors still doubt that the company can turn a profit or sustain its dizzying revenue growth. But the offering raised $700 million for Groupon,
which buys some time for Mason's brainchild to prove its business model.