Courtney Rubin:

So Johnson, 22, did the 21st century equivalent of griping to the kitchen staff (or the bartender down the street): She vented on Facebook. “Thanks for eating at Brixx,” she wrote, “you cheap piece of —- camper.” (For the record, the $5 tip was 17 percent of the customers’ bill.)

Within 48 hours, her managers came calling. They showed her a copy of her Facebook comments and fired her for breaking company policy forbidding insulting customers. A Brixx official told the Charlotte Observer she also violated a second company policy: Speaking ill about the company on social networks. According to the company, Johnson signed her agreement to these policies when she was hired.

My question: Why do people think that what they post online is private?