Kakao Talk, a mobile messenger highly popular among smartphone users in South Korea, might come off as a closed, private platform that you could safely share critical comments about others with your friends. Think twice: Such comments could get you to real legal trouble.

In a recent court ruling, a Korean man who spread rumors to nine people on his Kakao Talk messenger list during the 19th general election was fined 5 million won ($4,600) for violating the Public Official Election Act.

In another case, a man in his 20s threatened his ex-girlfriend by sending untrue messages about her to 40 people. The prosecution indicted the man for libel but he narrowly escaped punishment as he settled the case privately with his ex-girlfriend.

“Kakao Talk could be used as a tool to spread false rumors. Caution on the expressions is advised as messages can be shared in public space,” said an expert from a leading law firm.

Legal experts are now suggesting that people should remain cautious about using their mobile and online messengers, largely because such platforms are not viewed as a private space.

One of the reasons for classifying Kakao Talk and other mobile messengers as a sort of open and public platform is that these apps allow users to circulate rumors at a rapid pace in a way that hurts innocent victims.

Experts warned that those who send photos of people to others without their permission are at risk of prosecution.

Users, meanwhile, said that authorities should set up and publicize clear provisions about mobile defamation cases in connection with social networks and messaging services including Kakao Talk.

The number of Kakao Talk users has surpassed 80 million worldwide and 35 million are estimated to be Korean.

By Park Han-na  (hnpark@heraldcorp.com)