Facebook’s No. 3, Chris Cox, is leaving after privacy pivot

One of the key architects of the Facebook social media and advertising platform, chief product officer Chris Cox, is leaving the company after 13 years.

After CEO Mark Zuckerberg and COO Sheryl Sandberg, Cox is the third highest-ranking executive at Facebook, representing the engineering and product sides of the company. As of last spring the heads of Instagram and WhatsApp report in to him. He was also seen as a standard bearer for Facebook’s internal culture, which means that his departure may say even more about the company’s future.

Cox’s bombshell comes just one week after Zuckerberg announced that Facebook would become a “privacy-focused” company.

A long-time Zuckerberg confidante, Cox’s departure timing suggests he may not have been on board with the new corporate vision. “This will be a big project and we will need leaders who are excited to see the new direction through,” he said in a Facebook post on Thursday.

In addition, Cox wrote:

“For over a decade, I’ve been sharing the same message that Mark and I have always believed: social media’s history is not yet written, and its effects are not neutral. It is tied up in the richness and complexity of social life. As its builders we must endeavor to understand its impact–all the good, and all the bad–and take up the daily work of bending it towards the positive, and towards the good. This is our greatest responsibility.”

Facebook’s stock is off 2% in after-hours trading on Thursday.