North Korea launched a rocket on April 12, 2012, despite international warnings of censure  and further isolation. But to its embarrassment, the rocket disintegrated right after the launch and its remnants fell into the sea. This incident stirred up numerous debates in South Korean Internet space.
An instant reaction on the news of rocket launch was tut-tutting over the astronomical amount of money wasted on its unsuccessful launch, which could have been used to feed millions of starving North Koreans. A comment by Kim Sun-jun read  [ko]:
1년치 옥수수를 다 태워 버렸네.
They burnt away [the cost of] a year's amount of corn (which could have fed North Koreans) [note: corn is originally a supplementary crop but has become one of the major crops in North Korea after the country suffered from a serious shortage of rice for decades]
North Korean soldiers look south while on duty in the Joint Security Area, Korean Demilitarized Zone. Image is in the public domain, via Wikipedia.
Yoon Jae-won (@yjw23_kseri ), a North Korean analyst at the Kim Kwang Su Economic Research Institute, wrote six tweets which have been retweeted numerous times by other users. After condeming  [ko] North Korea's rocket launch as a ‘reprehensible act’ which could ruin current six-party talks , which are slowly progressing, Yoon then questions  [ko] public belief in the effectiveness of international sanction:
그런데 북한을 어떻게 다룰 것인가 하는 것은 현실적인 측면을 고려할 필요가 있습니다. 유엔안보리를 통해 북한을 비난하는 것은 자연스러운 반응이지만, 북한에 강경대응으로만 일관했을 때 더 큰 문제를 불러일으킬 수 있기 때문입니다.
But we need to get realistic in handling North Korea. It is only natural to blame the North through the UN Security Council, but this kind of hawkish approach and single-handedly using such an approach may backfire and bring bigger problems in the future.
Yoon further explains  [ko]:
제재로 일관하는 것은 국제사회에서 북한을 더욱 고립시킴으로써 오히려 김정은 체제의 내부결속을 다지는 결과를 초래하게 될 것입니다. 이런 상황일수록 이명박정부가 상황을 관리하고 북한을 고립시키지 않음으로써 개혁개방으로 유도하는 것이 중요합니다.
Using the international sanction as the one and only [diplomatic strategy] will further isolate North Korea from the international community. And it will also solidify Kim Jong-un's [the country's current leader] grip of power by making people gather under his name. Lee Myung-bak's [current president of South Korea] administration should be able to take control over this situation and try not to isolate them further in order to lead North Korea into revolution and the open market.
Daum Agora forum user stkt  refuses to use the word ‘ failure ‘ [ko] in describing North Korea's rocket launch, since there is no failure in sceintific experiments, especially in the space development program:
로켓발사는 애당초 실패라는 개념이 일반적인 실험과 다르다.일반적인 무기실험과 달리 로케트는 발사를 해봐야 실험 데이타를 얻는다. 로켓발사 실험에 있어서는 실패와 성공의 기준은 무엇이 잘못되었는지를 확인할 수 있는 실험 데이타와 노하우를 얻었는지의 여부인 것이지 기체의 발사결과 자체가 아닌 것이다.
The common usage of the term ‘failure’ in ordinary experimental situations does not really apply to rocket launches. Unlike regular weapons experiments, the only way to get data is by actually launching a rocket (in the case of rocket experiments). What matters here is whether they have succeeded in pulling out meaningful data during the experiment and whether they have learnt a lesson, NOT whether the rocket itself has launched alright.
Daum Agora user Ceasurs21  introduces  [ko] an interesting perspective:
북한의 로켓 발사가 실패했다는 소식이 반가우면서도 한편으로는 로켓 발사와 관련된 북한사람 중에 얼마나 많은 사람들의 목이 달아날까도 생각해 봤습니다.핵심 기술을 가진 과학자야 빳다 맞고 목숨은 건지겠지만 누군가는 책임지고 수용소에 끌려가거나 죽는 사람이 생길지도 모른다는 생각하니 씁쓸하네요. […]우리나라 사람중에서도 고초를 겪는 사람이 있습니다.다름아닌 주식투자자입니다. 며칠전 북한의 로켓 발사가 임박했다는 소식이 전해지자 방위산업 관련주들이 테마주에 편입되면서 급등했습니다.
Although I welcomed the news of North Korea's unsuccessful rocket launch, at the same time, I was concerned about the perilous lives of North Koreans who are involved in its rocket launch programs. In the case of scientists who have the core knowledge on the program [this] would save their lives after being beaten [by the government], but I felt really sorry for [ordinary] scientists who will be dragged into a prison camp for their failure.[…] And there are South Koreans who will suffer from this launch failure: stock investors. When news on North Korea's impending rocket launch broke out in the past few days, there was a sharp spike in the value of bundled stock packages that include stocks in the security and defense industries.
Daum Agora user 이건좀아니다 , after explaining about North Korean's brinksmanship strategy, complains  [ko] that since its threat patterns have not changed for decades, it is the South Korean government's turn to come up with effective strategies to handle such a dire situation.