Koum, along with WhatsApp's other founder, Brian Acton, sells WhatsApp on Facebook in 2014 for $ 19 billion. Approximately US $ 3 billion of which is a share of Facebook given on Koum.
Acton has decided to leave the company in September. Koum confirms his decision to go to the Facebook post. In his uploads, Koum did not discuss the problem at WhatsApp.
This implies that Koum does not believe in how Facebook regulates the privacy of user data and also their data encryption.
"I went at a time when people used WhatsApp in a way I never imagined before." WhatsApp team is now becoming very strong and they will continue to do great things, "Koum said.
"I took the time to try to do other things I like besides technology, like fiddling with my cars and playing frisbee, I'm still going to continue supporting WhatsApp from the outside, thanks to everyone who lets me get through this trip," he said.
Facebook CEO Mark Zuckerberg replied to Koum's post. "Jan, I will miss working with you," he said.
"I am grateful for all you have done to connect the world and everything you teach me, including the encryption and the ability to transfer the power of a centralized system and return it into the hands of the people." The values will remain the focus of WhatsApp.
Both Koum and Acton are privacy advisors. Both promise that they will continue to protect the privacy of WhatsApp users when they announce sales to Facebook four years ago.
That means, they never want to require users to integrate their WhatsApp account with a Facebook account.
However, Facebook encouraged WhatsApp to change some of its rules last year so they could get access to WhatsApp users' phone numbers.
In addition, Facebook also encourages the creation of a combined profile of users of their products Facebook, WhatsApp and Instagram so that profile can be used to collect user data and targeted ads.
WhatsApp business model becomes one of the things that Koum debates with Facebook. The giant social media wants to wipe out a subscription fee of US $ 0.99 per year to increase the number of users and wants to rely on advertising to earn revenue.