[kijin]

An attack sponsored by the South Korean government sounds unlikely. South Korea isn't exactly a bastion of free speech, but it isn't China, either.

If by "nationalists" you mean the notorious online community known as ilbe, that's definitely possible. They're a weird amalgam of political ideology and lulz, basically the neocon counterpart to /b/.

But it could just as well have been a shady competitor who got pissed off with Telegram for whatever reason. The social networking market in Korea is cutthroat. Almost everyone treats it as a zero-sum game where you have to destroy all the others in order to succeed. Maybe this competitor was planning to launch what it considered a killer feature and Telegram launched it first. Stickers?

[brobinson]

Interesting, I hadn't heard of "iibe". Here's an article I found in case anyone else is interested: http://www.koreabang.com/2012/features/netizen-explains-root...

[Laforet]

The linked post seems to point blame at LINE. Stickers (large animated emoticons) are a major source of revenue for LINE; if Telegram were to offer it for free then it will really hit their bottom line.

[brobinson]

The majority of LINE users are in Japan and Taiwan. It's the biggest program in both of those countries. LINE is owned by a Korean company, though.