By now you'll have probably heard of Breanna Mitchell, the teenage girl who posted a selfie smiling at Auschwitz concentration camp.
Although she posted the photo some time ago (June 20th), it has only recently gone viral - clocking up more than 3300 retweets and a barrage of abuse over the past few days.
In response to accusations of insensitivity and ignorance, Breanna claims that she took the photo in memory of her late father, after visiting the site on the anniversary of his death. She says they used to study the Holocaust together, but he died before they had a chance to visit. "That trip actually meant something to me and I was happy about it," she tweeted.
Despite this explanation, which sounds fair enough to me, the abusive tweets keep coming.
Her well-meaning post (which may have been bad taste - more on this later) has brought out the worst side of social media - its vicious pack mentality.
Relentlessly hounding a teenage girl is hardly angelic behaviour. In fact, it's downright bullying.
This isn't the first time people have been unfairly hounded the second they say or do something ill-informed online. And, sadly, it won't be the last.
Earlier this year 20-year-old Gemma Worrall was mauled for misspelling Barack Obama "Barraco Barner". There's no doubt that this is a hilarious error. Within minutes the comment had been retweeted more than 7,000 times, and the British beautician found herself unwillingly at the centre of jibes about "dumb Britain".
Similarly in 2012, 20-year-old Georgia Ford was forced off Twitter after innocently asking: "Is Wimbledon always held in London?" Twitter users attacking, forcing an embarrassed Georgia to delete her Twitter account.
This kind of behaviour wouldn't seem out of place in a school playground. But for some reason, it is fair game online - the playground has become the internet and the school kids are adults.
But back to Breanna... Her picture, although having a personal significance, is understandably going to cause offence. The Auschwitz I and Auschwitz II-Birkenau sites were the largest concentration camps, claiming the lives of more than 1,100,000 million men, women and children.
Standing at the camp may have been a significant moment for Breanna, but why did she have to tweet the photo? In doing so, she opened herself up to millions and millions of (often angry) Twitter users, and was probably not the best idea.
Her picture reignites lively discussions of appropriateness and responsibility in a social media age. With funeral selfies (we're looking at you, Obama) and hashtags such as #Yolocaust (yes, it's a thing), it's clear we're still working out boundaries of what is appropriate.
But while people, Breanna included, should be taking responsibility for what they post on a public forum, Twitter users need to stop ripping others to shreds like a pack of rabid dogs.