Three teenaged girls threw themselves off a building in Busan last October in what is believed to have been contacts made through suicide prevention websites on the Internet.
The all lived in separate locations _Busan, Gwangju and Daejeon _ but got together to kill themselves anyway.
Much of the contacts made through the Internet has reportedly died off but they are active on community sites as well on social network services.
The Cyber Terror Response Center at the National Police Agency said there have not been a single case of contacts made for collective suicides in general websites but 2,250 were detected in various portal sites and community cafes.
The Korean Communications Commission requested corrective action in 246 cases in 2012, which is 20 times more than that in 2011.
In most cases, as on Kakao Talk, people openly invite others to get together for a communal suicide, asking for recommendations of friends who may be interested as well.
One employee at a portal site said as many as 500 employees are taking three shifts around the clock to monitor such postings and taking them down immediately but they keep coming back on.