For Jang Mi-na, a 21-year-old college student in Seoul, Facebook used to be an integral part of her life: She used it to record her daily experiences, communicate with her friends and acquaintances, and stay informed about what they were up to.

But the social networking service became a source of privacy fears when she found out three years ago that a stalker was frequenting her account to keep track of her whereabouts and what she was doing.

“I was flabbergasted when a stalker came to meet me after he gleaned the information on my location from my Facebook account. Fortunately, I was surrounded by my friends, who asked him to step away from me,” said Jang.

“Since then, I have been very careful not to leak any of my personal data ― a reason why I am very sensitive about the privacy settings of my SNS accounts. These days, I just handwrite in my diary rather than writing online, and prefer to talk with people offline rather than meeting them online.”

Jang is one of many people who feel increasingly concerned about the possibility of their personal data being acquired by complete strangers, possibly with ill intentions, and of their privacy being infringed on.

Social media, supposedly a hub of shared information, often becomes a channel through which crooks can steal digital identities and undermine individuals’ online reputation overnight.

Kim Min-kyu, a musician and college instructor, came to realize the perils of depending too much on social media four months ago when his Facebook account was hacked.

“Somebody broke into my Facebook account and clicked the ‘Like’ button for some obscene adult sites. Many of my students who were linked to my account found out and started to look at me with suspicion,” said Kim.

“So, I hurriedly deleted it all and created a new account. But it was too late.”

Kim’s unpleasant experience with social media is not an isolated case, however. According to a survey conducted in April by the local job search portal Alba Heaven, 7 out of 10 respondents said they were seriously worried about potential privacy violations and personal data leaks.

When asked what worried them most with regard to privacy violation, nearly 40 percent of the respondents said that they were concerned that a stranger could easily contact them through SNS. Some 22 percent said they were worried that their past online postings would remain undeleted somewhere for good.

Amid growing privacy concerns, a growing number of people have started to opt for “private” social media such as Band and Kakao Talk and refrain from using “open” services such as Facebook and Twitter.

A recent survey by the KT Economics & Management Research Laboratory found that the number of Korean users of private social media has exceeded that of the open services since last September.

The number of monthly active users in Korea of the five private social networks including Kakao Talk surged to 13.2 million in February this year from 5.03 million in March 2013. Facebook, Twitter and the now-defunct MeToday saw their combined active user base edge up from 8.65 million per month to 11.9 million during the same period.

The number of monthly active users, or MAU, is a way to measure the success of a service.

The emergence of big data has also added to the deepening privacy concerns. “Big data” refers to the new ways in which businesses and other organizations are combining various digital data sets, and using statistics and other analytical tools to find hidden information or meaningful correlations from the data.

Many firms have begun using big data to analyze customers’ preferences and map out marketing strategies. But the process of data collection and analysis, and the resulting outcomes, have triggered a controversy over privacy violations.

A pharmaceutical company could use big data to analyze a consumer’s purchasing patterns and detect medical conditions. For example, the company could ascertain if a woman was pregnant or even infertile.

To assuage public concerns about privacy violations, the Korea Communications Commission, the country’s broadcasting regulator, has been working to create guidelines that would prevent the misuse of personal data while boosting the big data industry.

“In the past, information flowed from one person to another through gadgets. But now, information flows between people and gadgets, and from one gadget to other gadgets,” said Jong Young-su, a big-data expert at the National Information Society Agency.

“Amid this spread of information, we could leave our personal data somewhere even if we did not intend to, and someone else could track, analyze and use it for marketing purposes. This could violate your privacy.”

By Song Sang-ho (sshluck@heraldcorp.com)