Good satire is a generally believed to be writing that seeks to point out flaws in society and its institutions. Satirical writing can also be used to criticize the actions or policies of important public figures. Good satire typically uses humor and sarcasm to poke fun at institutions and public figures, with the goal of reforming society or politics. Often, however, satire appears to address archetypal figures, rather than particular individuals. Authors of good satire are usually advised to assume that their readers are intelligent enough to understand the humor of the piece, which may be exaggerated or understated, depending on the nature of the satirist's audience.
Literary scholars generally divide satire into three categories, named for ancient Greek and Roman authors who are believed to have been some of the first writers working in the genre. Juvenalian satire is named for the Roman author Juvenal, whose satirical works are typically identified as somewhat acerbic and often hostile in their mockery. Horatian satire is usually considered far less caustic, and generally attempts to paint its subjects as foolish rather than corrupt or depraved. Horatian satire often encourages the reader to laugh at himself, as well as at the subject of the satire. Menippean satire, named for the Greek author Menippus, is a type of satire that mocks the world at large, rather than focusing on a single subject or personage.
Writers of good satire usually employ wit and sarcasm rather than obscenities or unpleasant personal attacks. The satirical author is usually most successful when he caters to his readers' level of understanding. Different types of audiences will generally find humor in very different things. It's also considered important that the writer of good satire understand and cater to his readers' knowledge of the subject. Readers who possess detailed knowledge of the satire's subject matter will be more likely to understand the humor in the satirical piece.
It is typically considered both prudent and effective to remain within the limits of appropriate social taste when writing good satire. Some have warned that satire written in poor taste can be dangerous to its author and even to society at large, since the subjects of satire often don't enjoy being mocked. The use of subtlety, ambiguity, and innuendo can help the effective satirist to protect against crossing this boundary. Caricature, parody, irony, and sarcasm used in satire can be kept on the less caustic side, to avoid causing dangerous offense.
Satire as a literary genre has a long history, stretching back to the time of ancient Greece. Famous satirists in history have included authors Jonathan Swift, Geoffrey Chaucer and Mark Twain. More modern satirists include author Sir Terry Pratchett, television personality Jon Stewart, and cartoonist Gary Trudeau.