Korean Idol

K pop—a certain Asia-enveloping strain of contemporary Koreanpop music—is ­characterized by upbeat, hook-heavysongs and teary ballads, performed by highly choreographed boy bands and girl groups whose members generally range in age from fourteen to twenty-three. The most prominent of these are known as “idols.” They are the source of traffic jams and barricades in Seoul as they move from place to place. When they travel, legions of fans swamp airports, from Japan’s Narita to New York’s JFK, hoping to catch a glimpse of their idols; indeed, some devotees fly into these airports just for these brief moments.

But Kpop fandom has its stalkerish element. Jaejoong, a Kpop idol who resembles a manga protagonist, recently took to tweeting against sasaeng (short for “private-life fans”), the most crazed of fans, who shadow him relentlessly, whether it’s on his daily trip to the hair salon or a vacation to Tahiti. Such microscopic attention is made possible by the so-called “sasaeng cabbies,” who cruise around Seoul trying to spot the idols’ cars, tipping off the sasaeng in exchange for cold hard cash.

The sasaeng, naturally, are also diligent recorders, with thousands of blogs dedicated to their idols’ whereabouts. These sites are updated daily, sometimes hourly, albeit in code. For example, a post reading “Exit palace. G R O K. 85. What did I tell you? Kekekeke. Enter palace” means that the idol left his house, went to a karaoke bar in a car with a license plate ending in 85, and is now back at home. “Kekekeke” is meant to mimic laughter.

The sasaeng look down on the gongsunee (“official fans”), who take pride in showing up only for the “official” activities of their bands. Meanwhile, the gongsunee think the sasaeng are batshit insane. Online, epic ­battles ensue, with daily readers’ comments sometimes numbering in the tens of thousands on gallery portals like DC Inside. Usually, the gongsunee attack the sasaeng for violating privacy and sometimes endangering the lives of their idols. ­Members of JYJ have been in car accidents trying to elude sasaeng cabbies. And in a highly publicized 2006 ­incident, a sasaeng anti-fan of TVXQ’s Yunho spiked Yunho’s drink with superglue, sending him to the hospital.

At concerts in Seoul, different fan clubs hand out business cards, trying to recruit individual fans who have yet to select their bandwagon. But all ­defer to the jjang fans. Their activities include organizing charity donations and blood drives in...