Randi Zuckerberg, the sister of Facebook founder Mark Zuckerberg, got caught up in a debate about the handling of a private photo posted on the social media site after a family snapshot she thought she had only shared with friends made its way onto Twitter. The photo showed the Zuckerberg clan joyfully reacting to Facebook’s new Poke app. Zuckerberg, Facebook’s former head of marketing, claimed she had only shared the photo with her friends via the social media site. However the snapshot went public after Callie Schweitzer, a representative for Internet media firm Vox Media, reposted the shot on Twitter....