MOON JAE-IN briefly assumed the face of a badly bruised schoolboy. But it was not because he had botched a diplomatic mission or caused a political scandal. Rather, the reason was celebratory. South Korea’s president had donned a mask showing the protagonist of a popular web-based comic about bullied teenagers, to mark manhwa (comic) day and popularise his country’s latest export hit: webtoons, serialised comic strips that people can read on their phones.Listen to this storyYour browser does not support the element.Enjoy more audio and podcasts on iOS or Android.Webtoons began life in the early 2000s when Naver and Daum, the country’s biggest search engines, hired cartoon artists to design online comic strips. They were supposed to attract more visitors to their websites rather than generate income. But over the past decade the market has grown tenfold, making webtoons a vital source of income for the internet companies. More strikingly, they have begun to attain a degree of influence over global culture that belies their humble origins.For readers of webtoons, the advantage over more traditional comics lies in the variety of storylines and in the interactive features, animations and dramatic background music. After finishing an episode, fans can hit the comments section and debate the twists and turns of the plot with others. Lim Hyun-jee, a 26-year-old from Seoul, likes being able to read new episodes on her phone on her way to work rather than lug around hefty volumes of Japanese manga (comics or graphic novels), which she also enjoys. Jacqueline, a 21-year-old fan in Canada, says plots about girls discovering make-up and meeting hot guys make a nice change from standard superhero fare.But the success of webtoons is not restricted to comic lovers, says Jang Min-gi from Kyungnam University. Some of the cartoonists who started with Naver and Daum years ago have found themselves consulting on films and television dramas, raking in thousands of dollars. “Sweet Home”, a horror webtoon about a man surviving a virus that turns humans into monsters, was made into a drama last year and became the most-watched show on Netflix in eleven countries (a scene is pictured). Shows like “Itaewon Class”, about an ex-con trying to sort out his life, or “Cheese in the Trap”, which follows the romantic troubles of a group of students, have had success too.Ms Jang thinks this will eventually draw even more people to webtoons, as film versions of Spider-Man or Black Panther did for Marvel comics. “Most of today’s Marvel fans saw the films before the comics. It’s the same with webtoons. They are creating their own universe.”This article appeared in the Asia section of the print edition under the headline “Striding the universe”