Lee Su-jin used to work at a love hotel in South Korea, changing sheets and cleaning up after couples who had paid for a few hours of privacy. Sixteen years on, he is using the knowledge he gained to transform the industry.

Lee is founder of Yanolja, which makes South Korea's most popular app for booking rooms at short-stay lodgings, which South Koreans call motels. He is trying to persuade owners to stop focusing on sex and alter their facilities to appeal more to business travelers, families and tourists.

"If all the motels relied on love, they'd starve to death," 39-year-old Lee said in his office in Seoul's ritzy Gangnam neighborhood.