A long-time Zuckerberg confidante, Cox's departure timing suggests he may not have been on board with the new corporate vision.
Cox was a critical executive at Facebook, working there for more than a decade, helping design and run the news feed and then rising in the ranks to oversee all product at Facebook. Cox, who has been with the company for 13 years, announced his departure in a blog post Thursday without explaining what led to his exit. Both men are long-serving Facebook veterans - Cox was one of Facebook's earliest employees, and Daniels has been with the company since 2011 - and trusted lieutenants of Mark Zuckerberg.
Zuckerberg said Cox first mentioned he might leave a few years ago, but made a decision to stay on after 2016 as evidence emerged that Russians had manipulated Facebook's services to provoke discord in the US and influence the election won by President Donald Trump. It also means that Zuckerberg will seize control of Facebook's key products by making the leaders of its most important properties like Facebook, Instagram, and WhatsApp report directly to him-at least for the near term.
He's joined on his way out the door by Chris Daniels, Vice President of WhatsApp. In a note to employees about Cox's departure, Zuckerberg said Cox had been talking to him for a few years about doing something else but chose to stay after 2016 to help improve the social network.
The departures of Cox and Daniels come a day after a technical issue that limited use of Facebook and Instagram for most of Wednesday.
That effort will include introducing WhatsApp encryption technology to Facebook's Messenger app and Instagram's messaging option.
Longtime Facebook executive Will Cathcart will now lead WhatsApp. Once its other apps are included, this rises to 2.7... Zuckerberg is also promising to make photos and posts automatically disappear from public view.
Forrester analyst Jessica Liu said it sounded like Cox was "subtly disagreeing" with Zuckerberg's privacy memo, based on Cox's farewell post. In October, Oculus co-founder and former CEO Brendan Iribe announced he was leaving the Facebook-owned virtual reality company.