If a report from All Things D is true, and it looks like it probably is, considering that the letter of resignation is embedded in the piece, Randi Zuckerberg, Facebook’s director of marketing, who also happens to be the sister of CEO Mark Zuckerberg, is leaving the company.

Apparently her new company will be something called RtoZMedia, as she told Facebook’s Sheryl Sandberg and Elliot Schrage in the letter, to reach her at her new company, including an email address: [email protected]. There’s nothing at RtoZMedia.com but a placeholder page at this point.

“Be assured I will continue to be a strong, vocal evangelist for the most incredible social platform ever created,” she said in the letter. She also listed her work with Facebook that she was most proud of, which included things like the ABC News/Facebook Presidential Primary Debate in ’08, the CNN/Facebook Inauguration Partnership in ’09, the ABC/Facebook Live Election Night coverage in ’10, the Davos/Facebook partnership for the World Economic Forum, and the launch of Facebook Live.

She said these things all have one thing in common in that they “revolve around the intersection of traditional media and social technology,” which from the sound of it will be the focus of her new endeavor. “Now is the perfect time for me to move outside of Facebook to build a company focused on the exciting trends underway in the media industry,” she wrote.

I guess Facebook should be glad she’s not going to Google. A report today has Facebook in “panic” mode and lockdown over Google’s social network. BusinessInsider points to a Quora post voted up by a Facebook engineer saying, “I work with Facebook engineering, and I can say the answer is kind of, not exactly, maybe, sure. We are in lockdown. It’s official; you can see the lockdown sign lit up in the offices. It’s no secret. However, the first suggestion I saw of a lockdown was a week before G+ came out. It was posted on an internal group and had over 50 likes when I stopped paying attention.”

Zuckerberg was in the news earlier this week, receiving attention for saying, “Anonymity on the Internet has to go away” during a discussion about cyber bullying. “People behave a lot better when they have their real names down,” she said, according to the Huffington Post. “I think people hide behind anonymity and they feel like they can say whatever they want behind closed doors.”

Update: Zuckerberg tweeted the following: