Twitter user @cshweitz shared a photo of the Zuckerberg family checking out Poke on Wednesday, the latest mobile app developed by Facebook and dubbed by Business Insider as "sexting-friendly". Poke is similar to Snapchat, an app which is popular with younger age users, and which has gained a reputation as a tool for sending risque images known as "sexts".
The picture shared - which shows those in it reacting to Poke on their smartphones - had originally been posted on Facebook by Randi Zuckerberg, who expressed her displeasure with the photo being shared publicly on Twitter.
"Not sure where you got this photo. I posted it to friends only on FB. You reposting it to Twitter is way uncool," Zuckerberg tweeted to @cshweitz, according to a screenshot of the tweet grabbed by BuzzFeed.
The Twitter user, Callie Schweitzer, apologised, explaining that she follows Randi Zuckerberg on Facebook and saw the picture at the top of her News Feed.
Randi Zuckerberg said she accepted the apology a few minutes later and explained that Schweitzer probably saw the picture because Schweitzer is Facebook friends with Randi Zuckerberg's sister, who was tagged in the photo.
Many of the tweets by both users, including the one with the photo, have since been deleted.
Photos that have been tagged are visible to friends of every user in the photo, not just the friends of the user who posted it. It is one of the loopholes in the social network's privacy feature that some users say should be plugged.
Many Facebook users choose to share content using the "friends of friends" option. According to a study published earlier this year by Pew Internet, the median Facebook user, according to the Pew sample, has 31,170 friends of friends. This, some could argue, makes content shared to friends of friends not exactly "private".
"Digital etiquette: always ask permission before posting a friend's photo publicly. It's not about privacy settings, it's about human decency," Randi Zuckerberg tweeted after the photo was removed.
Users frequently complain about the social network's confusing privacy settings, and with Randi Zuckerberg, a former Facebook staff member, falling victim to them, some users haven't been shy about voicing their complaints.
"This is absolutely about privacy settings. That person shouldn't have seen it. Your brother's site is doing this to us all!" a user responded to Randi Zuckerberg's tweet.
Dan Lyons, editor-in-chief of tech blog ReadWrite, wrote that lots of people had a laugh about how Randi Zuckerberg's incident showed "again how stupid and confusing Facebook's privacy settings are".
Mario Aguilar, an editor of tech blog Gizmodo, wrote that if Randi Zuckerberg didn't understand her privacy settings, and how a photo on Facebook might suddenly be made public, then that was "her problem".
Randi, 30, who is in a band called Feedbomb, is behind a Silicon Valley reality show shown earlier this year in the US which was dismissed by PandoDaily.com as "like Jersey Shore only without the tans". The website said it depicted people "drinking, shirtless in clubs and standing in front of a walk-in closet of suits as some sort of 'insider look' at Silicon Valley."
Randi was moved by the criticism to justify her involvement in the show with a long Facebook post: "This is reality TV, not a documentary. The show isn't meant to represent all of Silicon Valley, but to authentically follow the lives of a few young people trying to blaze their own trails."
In a Twitter message posted today, Randi said the topic of online etiquette elicits "passion, debate, anger & Twitter crazies" to the extent that it might be the subject of her next show.
LA Times with Fairfax Media and AFP