Billionaire Hiroshi Mikitani´s company Rakuten buys Viber Internet messaging and calling service for $900 million. Billionaire Hiroshi Mikitani is called “Miki“.Estimated net worth of $6.4 billion Rakuten CEO Hiroshi Mikitani explained in a Tokyo press conference that the company sees Viber as “the most consistently high quality and convenient messaging and VoIP experience...