The overall purpose of satire is usually to make some kind of moral or political change in society through the use of critical humor. A satirist will choose a subject or person with whom he finds faults and use humor to make those faults obvious. In theory, many satirists hope that the humor will have a corrective effect, almost like a punishment for bad behavior, ultimately leading people to change the way they behave and discouraging others from behaving the same way in the future.
Since the overall purpose of satire is generally to point out the faults in people, satirists often rely on exaggeration to make a point. For example, a politician who favors heavy taxation might be depicted as a pig stealing people’s food from their plates. This sort of exaggeration shows the fault in question and puts a critical spin on it. People often remember and enjoy the satire because it’s funny and entertaining, but if it’s handled correctly, the message should ideally stick with them much longer than the initial entertainment element.
The terms "satire" and "parody" are often confused, but the purpose of satire makes it generally very different from parody. When people do a parody of something, they may rely on many of the same techniques that a satirist would use, including exaggeration, but their primary purpose is to make people laugh, and if the author doesn’t really care if there is a real political effect or not. Sometimes the lines between satire and parody can be blurred for a lot of different reasons. Some parodies end up working as brilliant satires in terms of effect, while some satires might miss the mark completely and have no more impact than a parody.
Since many artists consider the purpose of satire to be an important thing for society, satires have been created for nearly every artistic medium in existence. For example, a horror movie with a humorous slant, showing teenagers misbehaving and being chased by some kind of monster, can be seen as a kind of satire urging better behavior in the youth of society. A more classical example of satire is the political cartoon, which allows the satirist to explore the political issues of the day through the use of humorous imagery. Sketch comedy television shows like "Saturday Night Live" and American talk show hosts like Conan O’Brien and Jon Stewart often mix parody and satire at different times, with some moments more dedicated to pure humor while others aim to change public opinion or point out flaws in society.