Mark Zuckerberg's sister Randi quits Facebook to set up on her own

Set up on her own

Facebook founder's sister leaves social networking site to form company with no goal or employees – yet

Anyone who saw the film The Social Network would have no way of knowing that Facebook founder Mark Zuckerberg has a sister. But now Randi Zuckerberg is generating headlines of her own – after six years working faithfully in her younger brother's shadow as Facebook's director of market development, she is jumping ship to set up an independent social media company.

The tech bloggers of Silicon Valley are rubbing their hands at the prospect of some sibling rivalry to follow on from the multiple lawsuits that the younger Zuckerberg – he's 27, she's 29 – has endured over the parentage of his wildly popular website.

But older business analysts wonder if this may not be the online equivalent of the great Dunkin' Donuts rift of the 1950s, when one of the two original partners behind America's most popular snackshops broke out on his own with the rival Mister Donut franchise. (They were later bought by the same corporate parent and reunited after close to 40 years.) More perplexed tech watchers wonder what Randi hopes to achieve that she hasn't already done in one of the world's most rapidly expanding companies. Her new outfit has a name, RtoZ Media, but no publicly defined goal, no employees and no fully functioning website – yet.

Randi is unlikely to be planning anything excessively controversial. She appears to have decided to have fun with her money and her instantly recognisable last name to branch out on her own, without doing anything to damage the Facebook brand she worked for so long to help establish.

"I'm proud of what I've done here … but I know I'll be able to do just as much, or more, for Facebook once I'm on the outside," she wrote in her resignation letter last week. She said her goal was "to launch my own innovative programming and work with media companies", adding: "Facebook will clearly be a central element in all my projects."

She might not have a reputation as a cutting-edge innovator like her brother, but Randi is no slouch. She, too, went to Harvard, graduating in psychology at about the time Mark was dropping out to focus full-time on the phenomenon he had unleashed. At first, she thought she would study to be a cantor – the singer who accompanies the rabbi in Jewish services – but changed her mind when it became clear there was an irresistible new family business to join.

In Silicon Valley, she has always had a reputation as someone unafraid to let her hair down and have a good time. A few years ago, she made a music video, celebrating the demise of the erstwhile Facebook rival Friendster with a tongue-in-cheek ditty called Valleyfreude.

She has sung periodically since, and written a column for Tina Brown's online publication The Daily Beast. Her sense of fun is strictly of the non-scandalous variety, however: she has been with her husband, venture capitalist Brent Tworetzky, since they were both at Harvard. In her professional life, she has worked hardest to marry Facebook with numerous traditional media initiatives – broadcasting a presidential debate in 2008, bringing the World Economic Forum in Davos to Facebook's global audience and launching Facebook Live, which she used to relay a town hall meeting held by President Barack Obama.

Does that qualify her as a high-flyer on a par with her brother or Steve Jobs? Not exactly. But it probably sets her up nicely as a high-profile consultant to the great and the good of corporate America, who want to understand how to integrate social media into their marketing and customer outreach plans.

Just a couple of days before she resigned, Randi argued at a round-table discussion hosted by Marie Claire magazine that the best way to police social networking sites was to oblige everyone to use their real names. That did not endear her to the more radical online community, which believes anonymity and identity-shifting are all part of the great experiment of the internet.

It did, however, send a reassuring message to conservatively inclined executives who might otherwise be nervous of embracing a communication tool over which they have limited control. She is likely to be talking to a lot of those people in the coming weeks and months.