Lovers of irony take note: Mark Zuckerberg's sister Randi has complained about a Facebook privacy breach.

Randi, the former head of marketing for Facebook and the executive producer of Bravo's reality series Silicon Valley, complained when Callie Schweitzer, director of marketing and projects at VoxMedia, posted a photo of Randi and her family (including Mark) reacting to the new Poke app. Randi originally circulated the photo on Facebook to her friends, but Schweitzer posted it publicly on Twitter:

Zuckerberg and Schweitzer have since deleted the conversation, but according to BuzzFeed, Schweitzer originally wrote "@randizuckerberg demonstrates her family's response to Poke" with a link to the pic. Randi then replied "@cschweitz: Not sure where you got this photo. I posted it only to friends on FB. You reposting it on Twitter is way uncool."

Schweitzer then attempted to explain:

@randizuckerberg I'm just your subscriber and this was top of my newsfeed. Genuinely sorry but it came up in my feed and seemed public. — Callie Schweitzer (@cschweitz) December 26, 2012

@randizuckerberg totally fair. I would hate for a private photo of mine to be public and would never want to do same to others. — Callie Schweitzer (@cschweitz) December 26, 2012

@randizuckerberg fwiw, I thought the photo was incredibly endearing which is why I liked it. We never see humans on the Internet! — Callie Schweitzer (@cschweitz) December 26, 2012

Zuckerberg appears to be ignoring Schweitzer at this point but going public with a general beef about manners in the social media age:

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 (@randizuckerberg) December 26, 2012

The incident comes after Facebook privacy issues have recently come to the fore. The company suffered a pr debacle earlier in the month when Facebook unit Instagram attempted to update its privacy policies to allow users' photos to be employed by advertisers. The company backpedaled, however, after consumers complained.

Image courtesy of Flickr, World Economic Forum