[More from Mashable: Nielsen Ratings Coming to Facebook This Month]
The former Facebook marketing director will draw from her experiences developing the company's marketing strategy and its popular live video channel, Facebook Live. She was recently nominated for an Emmy for her work with Facebook Live. (Mashable recently teamed up with Facebook Live for its SXSW coverage.)
In a phone call with Mashable, Zuckerberg said that she thinks of the move as a "natural extension" and had been considering the move "for a really long time." With the success of Facebook Live and the Facebook-Obama town hall, she saw an opportunity to start her own company.
[More from Mashable: Facebook Buys iPad Book-Maker Push Pop Press]
"I had the momentum to do it now," she said.
The news, first reported by Kara Swisher at AllThingsD, will come as a shock to the Silicon Valley establishment. Randi Zuckerberg has been a pivotal figure in Facebook's growth, and her departure will create a void that not even her brother will be able to fill.
This story originally published on Mashable here.

