What's next for the team behind "The Walking Dead"? Skybound Entertainment is working on a show about a family coping with the knowledge that a meteor will pulverize the earth. And it will be in Korean, with a Korean cast.

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The pre-apocalyptic drama, "Five Year," which is planned for five seasons, is a sign of how the country's TV culture is reaching across the globe.

Korean dramas, or K-dramas, have been popular for years in Asia and have fans around the world, from the Middle East to Latin America. The shows are romantic and sometimes compared to soap operas, though they're free of sex and violence. A few are being developed as remakes for American TV. For now, their popularity is fueling opportunities for video-on-demand sites that air the dramas outside South Korea with subtitles and for brands that place products in them.

In China, 12 episodes of the Korean Broadcasting System hit "Descendants of the Sun," about the romance between a soldier and a surgeon in wartime, had nearly 1.7 billion views as of April 1 on a platform called iQiyi. That number isn't a typo: The show has more views than China has people. The platform is using the show to lure more subscribers onto its paid VIP service. K-dramas are huge in China, prompting epic binge-watching cases that have reportedly endangered people's health; the Ministry of Public Security has warned that they can be dangerous, alluding to the case of a man who underwent massive plastic surgery to look like a Korean actor.

In the U.S., meanwhile, Warner Bros. just bought DramaFever, an online video platform that airs Korean shows and other content to a global audience.

Viki is another burgeoning power player in the space. Owned by Japanese e-commerce giant Rakuten, the streaming platform is partnering with "The Walking Dead" producers on "Five Year," which will air on both Viki and Korean TV.

That series will start shooting this year; meanwhile, Viki's first original series, "Dramaworld," debuts this month. It's about an American college student who is obsessed with K-dramas and gets sucked into her favorite show.

Viki, which makes most of its revenue from ads but is pushing for more paid subscriptions, has several unusual embedded features. It's part video-streaming site, part community. Fans can post comments in real time during the show. One series, "She Was Pretty," had more than one comment for every second it aired.

Viki's programming is also subtitled through crowdsourcing, with fans translating dialogue voluntarily into languages from English to Romanian to Arabic. Such engagement appealed to "Walking Dead" producers Skybound Entertainment, which says Viki is "transforming the way viewers consume and translate media."

Dedicated subtitlers get perks, but that's not why they do it, said Viki CEO Tammy H. Nam.

"These are people who, in a lot of cases, regardless of where they live, feel a sense of deep connection with other fans, since they may be in an area or community that doesn't understand their love of the content as much," Ms. Nam said.

Of the platform's 10 million-plus registered users, 33% are in North America, 28% are in Latin America and 24% are in Europe.

K-drama is sometimes a gateway to a wider interest in Korean culture, food and brands. Rachel Carter, a writer of young adult novels in Vermont, tried them on a whim and got hooked. "I'm a longtime romance-novel reader, and I love alpha men, quirky heroines, jealousy and lovers torn apart by outside circumstances," she said. Ms. Carter also said she has picked up beauty tips from the show and has embraced a Korean skincare routine with beauty products she buys on Amazon and Memebox.

South Korea's government long ago embraced pop culture as a way to transform itself into Asia's trendsetter and fuel its economy. Product placement is huge in K-drama. Samsung phones and Hyundai cars make frequent appearances. In 2014, a global shortage of one shade of YSL lipstick occurred when rumor spread that the actress in Korean fantasy "My Love From Another Star" wore it. (She didn't, but the incident proved K-drama's power to move products.) The Korea Herald cited market observers who forecast that "Descendants of the Sun" alone will boost the Korean economy by $261 million, partly by driving demand for tourism and products.

Brands are taking note. South Korea's Cheil Worldwide has a team that digitally inserts brands into dramas and music videos after they're filmed. Recently, it added soymilk from Korea's Hanmi Medicare as well as the brand's signage to several episodes of China's version of "Descendants of the Sun."

Jin Choi, a member of that Cheil team, said other clients will be closely watching the impact in China. Going forward, he expects many Chinese brands will also want to be inserted into Korean shows, looking for a bit of K-drama cool to rub off on them.