Is the Internet a Mob Without Consequence? The immediacy and fast pace of the Internet can be magical. But when someone makes a comment that the masses disagree with, a mob with 140-character pitchforks can develop in seconds and the Internet can become terrifyingly bellicose. We saw this happen late-last week when Justine Sacco, now the former communications director for InterActiveCorp, better known as I.A.C., tweeted: "Going to Africa. I'm white!" before boarding a flight to Africa from London. The response on social media came quickly. And the speed with which it turned ugly was even scarier. At first the discussion around her tweet was relatively trivial, with people wondering if Ms. Sacco's account had been hacked. Yet as soon as it was clear that she had made similar comments in the past, the Internet turned into a voracious and vengeful mob. Ms. Sacco was tried and judged guilty in a public square of millions and soon attacked in a way that seemed worse than her original statement. Within hours, people threatened to rape, shoot, kill and torture her. The mob found her Facebook and Instagram accounts and began threatening the same perils on photos she had posted of friends and family. Not satisfied, people began threatening her family directly. The incident was a trending topic on Twitter and a huge forum thread on Reddit. This all happened while Ms. Sacco was on a 12-hour flight without Wi-Fi to Africa. When she landed, it was game over. She deleted her entire social footprint online, including her Instagram, Facebook and Twitter, and was fired from her job, effective 12 hours earlier. "This default to hate, this automatic mockery and derision, needs to be viewed with the same hatred as Sacco's tweet," wrote Tauriq Moosa, a tutor in ethics, bioethics and critical thinking at the University of Cape Town, South Africa. Indeed, more so, since more people do it, no one is arbiter of said hate, and it's constant, wide-ranging and terrifying if you're the target. Ms. Sacco is far from being the only target in these types of situations. Pax Dickinson, a chief technology officer for Business Insider, was forced to resign this year after tweeting comments that people found sexist. He too was subsequently attacked on the web, called names and rioted against, until he was ousted from his job. Daily there are countless other incidents of people being threatened and pummeled for something they have said online. One difference among these episodes, and the ones involving Ms. Sacco and Mr. Dickinson, is that these smaller riots aren't written about on blogs. But the relentlessness of the group is often the same. Mobs that start with a small spark and erupt in chaos have existed for centuries. As John Mullan, a professor of English at the University College London, noted in a lengthy piece about the history of mobs, in the past it was often the poor who rallied against the rich and powerful. But today's riots are different in that it is the powerful, specifically those with the largest followings online, that could help quell these eruptions, yet instead douse them with more anger and hate. Those not piling on with hate ended up egging on the others by treating the entire experience as if it were a reality TV show. Or a joke. Anyone who tried remotely to defend Ms. Sacco was then attacked, too. In the eyes of the mob, there was justice. Yet the people who threatened to rape and murder Ms. Sacco, who attacked her family and friends, aren't held in contempt or fired from their jobs. Jeff Bercovici, a staff writer for Forbes covering media and technology, wrote in a blog post that he knew Ms. Sacco and considered her a friend. Over drinks a few weeks ago, he wrote, Ms. Sacco explained that she had recently noticed that "people seemed to like the tweets that were just a little bit risqué or outrageous." Maybe that need to impress, to find validation through the people that follow us online, was what led to Ms. Sacco's inappropriate tweet, and also gave the people who attacked her the justification for their own vitriolic behavior.