A stunner: the man in charge of developing new ad units for Facebook, Gokul Rajaram, is leaving Facebook.
Rajaram is going to Twitter creator Jack Dorsey's payments startup, Square, to lead up product development.
It's a "big loss" for Facebook, a source close to the company tells us.
Every time one of Facebook's billion users look at an ad of Facebook, that person is looking at a product that was developed by a team led by Rajaram. In the past year, those ads generated around $5 billion for Facebook.
Rajaram broke the news to his team at Facebook in a meeting.
Our Facebook source tells us there is "no sense of negativity" about Rajaram's departure.
" Square dropped this great opportunity to run product for an entire company in his lap. He has also worked on ads for ages, I think he wanted to do something different."
In a statement provided to All Things D, Rajaram said, "I’ve been fortunate to work for two mission-driven, world-changing companies, and Square’s vision and passion for helping businesses grow is inspiring."
"I’m thrilled to join the team and help build amazing products that drive economic growth and empower local businesses around the world."
Rajaram joined Facebook in 2010 when it acquired the startup he was running with his brother, called Chai Labs. Facebook bought Chai Labs for one reason: to hire Rajaram.
Before Chai, Rajaram spent 5 years at Google, where his last job was Product Management Director, AdSense .
One ex-Googler we talked to for a story we wrote about Rajaram a year ago told us Rajaram "is a legend" and that he is "beloved times ten" by those who have worked with him.
"[Rajaram] sees the forest and the trees," says this source.
Former Googler and Associated Content CEO Patrick Keane told us then that "Gokul is a brilliant technologist and a skilled executive. He can deftly bridge the most sophisticated technical and business challenges."
"I worked with him closely at Google on the launch of AdSense and he was a key tech and recruiting asset on the board of Associated Content."
Another ex-Googler said Rajaram "is the man."
"He was key figure at Google in days of AdSense. He served as a translator between tech and business. Any time a business person at Google had a question about how our ad systems worked, they would go to him. That group of senior ads people from Google became even more senior at Facebook and wanted him to serve similar role there."
All Things D's Jason Del Rey says Rajaram will be replaced at Facebook by Mike Hudack, best known for founding video startup Blip.TV.
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