When I started my career at NBC, my office was located right across the hall from several screening rooms. The screening rooms were used by advertisers and their agencies to review episodes of programs they were considering sponsoring before they aired. It was a way for sponsors to make sure the content reflected their corporate values — or at least, would not reflect poorly on the product or company. If a television program included a car crash, for example, a car manufacturer might not want their ads to appear in the adjacent commercial break.