If you're a fan of sitcoms -- and in particular, those from before 2010 or so -- you're probably familiar with the "laugh track." In the 1950s, a television engineer named Charles Douglass invented something called the "Laff Box," which, basically, was a recording of audience laughter that could be added whenever show producers wanted to make it clear that a joke was intended to be a joke. As the New York Times noted in an obituary for Douglass, the Laff Box "is responsible for an incalculable number of poor sitcom jokes being greeted with bursts of unearned, prerecorded laughter," having inspired similar decades of sitcoms since.

But Douglass's innovation wasn't the first time show producers found ways to fake an audience's reaction. And in one case, it led to a tiny bit of extortion.

The idea of having some sort of cue when to laugh, clap, or cry isn't all that new, perhaps dating back to the Roman empire. Under the reign of Nero, the emperor from the year 54 until his death a decade and a half later, Rome built many amphitheaters across its territories, in part so that Nero himself could take the stage. He loved performing -- he was known to be an actor, poet, an more -- and, being the emperor, always was able to command an audience. But in his case, he took the idea of "commanding" seriously -- he was known to require soldiers to applaud when he performed in front of them. And of course, others followed suit.

In Nero's case, the participatory applause of the non-solider audience was probably, in part, encouraged by the fact that he was the guy in charge. But other producers found that the power aspect wasn't necessarily required for the ploy to be successful. In the 1500s, a French poet named Jean Daurant bought up some tickets to his own show and gave them out, for free, under a condition: the gratis entrants agreed to applaud his work, no matter how they felt about it. And by the mid-1700s, the idea spread to the French opera houses. Per London's Opera Holland Park's website, "theatres in eighteenth- and nineteenth-century Paris, whether in the spoken theatre, opera or ballet, would pay organized groups to bolster success for a production with their applause." 

These hired clapping hands, called a "claque" (from the French word claquer, which means "to clap"), quickly proved their worth. Show producers became increasingly interested in giving up a few seats to ensure that the right moments received the right reaction from the crowd. And shortly thereafter, a cottage industry emerged. The 1919 edition of the Encyclopedia Brittanica explains: 

[In] 1820 that a M. Sauton seriously undertook the systematization of the claque, and opened an office in Paris for the supply of claqueurs. By 1830 the claque had become a regular institution. The manager of a theatre sends an order for any number of claqueurs. These people are usually under a chef de claque, whose duty it is to judge where their efforts are needed and to start the demonstration of approval. This takes several forms. Thus there are commissaires, those who learn the piece by heart, and call the attention of their neighbors to its good points between the acts. The rieurs are those who laugh loudly at the jokes. The pleureurs, generally women, feign tears, by holding their handkerchiefs to their eyes. The chatouilleurs keep the audience in a good humor, while the bisseurs simply clap their hands and cry bis! bis! to secure encores.

The practice of hired applauders and, by extension, extortionists, mostly faded by the 1950s or so (about when the laugh track emerged, coincidentally). The exception? Russia. As of 2013, according to the New York Times, you'll still find claquers ready to work -- or else.