The reluctance to tinker with the show’s formula is no doubt attributable to the fact that since its debut in the fall of 2004, “To Catch a Predator” has been the rarest of rare birds in the television news world: a clear ratings winner. The show regularly outdraws NBC’s other primetime fare. It succeeds by tapping into something that has been part of American culture since the Puritans stuck offenders in the stockade: public humiliation. The notion of delighting in another’s disgrace drives much of the reality TV phenomenon, and is present in the DNA of everything from Judge Judy to Jackass to Borat. “Predator” couples this with a hyped-up fear of Internet sex fiends, creating a can’t-miss formula. The show’s ratings success has made it a sweeps-week staple and turned Chris Hansen into something of a pop-culture icon. To date, by the show’s own count, it has netted 238 would-be predators, thirty-six of whom have either pleaded guilty or been convicted. Hansen regularly gives talks to schools and parent groups concerned about Internet sex predators, and he was even summoned to Washington to testify before a congressional subcommittee investigating the problem, where he and Dateline received effusive praise for their efforts. When the comedian Conan O’Brien filmed a bit to open this year’s Emmy Awards that showed him parading through the sets of hit shows of every network, his last stop was a “Predator” house where Hansen confronted him and O’Brien gave a spot-on rendition of the sweaty, shaky dissembling that most of the show’s targets display.

All that is a long way from where “To Catch a Predator” started. The Dateline producer Lynn Keller says she first contacted the Perverted Justice group about the possibility of doing a show in January or February of 2004. Perverted Justice had already worked with several local television stations, including one in Detroit, where Chris Hansen knew one of the producers and had talked with him about a sting operation the station had filmed using Perverted Justice’s online expertise to lure targets. Dateline’s first sting house was set up in Bethpage, Long Island, about an hour outside of New York City. Hansen recalls being nervous that no one would show up and that he might have to explain to the network why he had blown a bunch of money on a flop investigation. “We thought we might get one person,” Keller recalls. They needn’t have worried. Before he could even reach the house for the first day of filming, Hansen got a frantic call from Keller that the first target was inbound. Hansen beat him there by just fifteen minutes.

The Long Island sting netted eighteen suspects in two and a half days. Eight months later, the show set up a sting house in Fairfax, Virginia (at a home belonging to a friend of Hansen’s in the FBI), and snared nineteen more men, including a rabbi, an emergency-room doctor, a special-education teacher, and an unemployed man claiming to be a teacher, who memorably walked into the house naked. The third show, filmed in early 2006 in southern California, drew fifty-one men over three days. But even as the stings expanded and ratings soared, critics inside and outside the network raised serious questions about whether “To Catch a Predator” was erasing lines that even an increasingly tabloid newsmagazine show should respect.

Douglas McCollam is a contributing editor to CJR.