The independence and protection of its users’ data is a core tenet of WhatsApp that Koum and his co-founder, Brian Acton, promised to preserve when they sold their tiny start-up to Facebook. It doubled down on its pledge by adding encryption in 2016. The clash over data took on additional significance in the wake of revelations in March that Facebook had allowed third parties to mishandle its users’ personal information.
Source: WhatsApp founder plans to leave after broad clashes with parent Facebook – The Washington Post