Deal activity in the messaging app sector is surging, as are valuations. On top of Facebook's recently announced $19B acquisition of WhatsApp, Rakuten, Japan's largest e-commerce company, has agreed to acquire Israeli messaging service Viber for $900M and Softbank is seeking to buy a stake in Line, the leading mobile messaging service in Japan. Much of the action is focused on Asia, with Line (controlled by Korea's Naver) dominant in Japan, Taiwan and Thailand, while Kakao Talk is entrenched in [...]