Propaganda is information that is designed to influence public opinions and behavior. The word is Latin, but took on new meaning in the 17th century in the Catholic church. In the 18th and 19th centuries, propaganda became a greater importance in the political area, with the growing of literate people, so the freedoms of press, speech, and assembly were demanded more. World War I was when they started using propaganda as a weapon to shape people's opinions. In the United States and Germany, propaganda became a term used with lies, and manipulation, during this time. Hilter wrote, 5 years after World War I, "Propaganda, is a truly terrible weapon in the hands of an expert."
Modern propaganda is used by advertising, communication, and mass psychology, by using techniques and strategies. It is always biased in ideas, by achieving a particular side. They only show one side to weaken or strengthen a case, and edit anything that could be percived as bad out of their advertisment. It is not always successful, it depends on the audience, and the message.