Have you ever thoughtlessly tweeted or Facebooked something … and then thought later, ugh, I shouldn’t have done that? Most of us have. And usually it’s no big deal. But sometimes, one misguided tweet or status update can be a very big deal. It can cost jobs, relationships, and reputations. That was certainly the case for PR executive Justine Sacco. She was fired after tweeting an insensitive AIDS joke that went viral, and then had such a hard time finding another job, she left the country. She’s just one of the people Jon Ronson wrote about in his new book, So You’ve Been Publicly Shamed. In it, he looks at what happens to the people at the center of these kinds of scandals, long after the news cycle and the public rage have moved on.