However, 18 months later, Facebook pushed WhatsApp to change its terms of service to give the social network access to the personal data of WhatsApp users. The popular service was developed in 2009 by Koum and Brian Acton, who left Facebook past year and has recently criticized WhatsApp's owner as a reckless abuser of user data. Acton left Facebook in 2017, and has since become a champion for encrypted messaging app Signal, going so far as to promote the #DeleteFacebook movement.
Koum joined Facebook when it bought WhatsApp for about $19 billion in 2014.
Acton, who left Facebook in September 2017, was one of the most startling people to declare their breakup with the social network, posting to Twitter in March: "It is time".
Koum confirmed on his Facebook page today that he's leaving, saying it is time for him to "move on". "The team is stronger than ever and it'll continue to do awesome things", he wrote in a Facebook post.
Koum, however, remained to serve as WhatsApp's CEO, a role he will be stepping down from, according to a post he published on Facebook. But in 2016, Facebook began collecting phone numbers from WhatsApp users so that it could offer better friend suggestions and show more relevant ads.
Koum's decision may be made easier thanks to the $10.4 billion fortune he's already accrued, according to the Bloomberg Billionaires Index.
The man who Mark Zuckerberg says taught him about the power of encryption is leaving the Facebook family. And Acton and Koum may be followed by an even larger falloff, as the WaPo report suggests November as a mass-exodus point, when original WhatsApp staffers will be allowed to exercise stock options. "Those values will always be at the heart of WhatsApp". Acton left the company a year ago and has since become an outspoken opponent to Facebook's handling of user data.