Japanese company Rakuten, the owner of Kobo e-readers and online retailer Play.com, is acquiring Viber for $900 million. Rakuten has an ambitious goal of becoming the world’s No.1 internet services company, and acquiring the Viber messaging and video calling app will help it access a global user base of more than 300 million users. Viber has seen impressive growth, particular in the Middle East and US, and it’s clear Rakuten wants to take advantage of that for its aggressive goal. With Viber, Rakuten has a lot of competition in a market that’s filling up with messaging and video calling apps. WhatsApp now has more than 400 million monthly users, and Skype has around 300 million users worldwide.