Tags Vuong Quang Khai Zalo has 15 million subscribers Wednesday, Aug 06, 2014 Vietnamese over-the-top (OTT) service Zalo had 15 million subscribers and had handled 185 million messages per day by the end of July. Zalo: Viet Nam falls in love with first home-grown OTT service Friday, Oct 11, 2013 Zalo, the latest offering from Vietnamese company VinaGame (VNG), hopes to win over new customers and foster their relationships with friends and family with its slogan Talk To Your Love.