some techniques are used to bring particular messages to particular groups. an example of this is the suggestion we see online that promote books similar to ones we have already bought. other techniques bring messages to the messages of the mass of the population. For many years, Mothers Against Drunk Driving(MADD) organized a big campain in North America to prevent people from drinking and driving. They used print and television ads to get their message across. As a result, drunk driving dropped in many American states. Some of these ads were so good they won award.