I've been expecting this. Every time that the world thaws and reaches out to work with North Korea, Kim responds with some sort of military action that says, "Now that you've given us what we want -

"
It's the same pattern repeating itself over and over - see definition of insanity.
In the past couple of weeks, North Korea has held "high level" talks with the U.S. about denuclearization. In spite of previous rhetoric, these talks were held strictly between the U.S. and the DPRK and did not include any of the other interested parties of the 6 nations. So once again, Kim got what he wanted.
In addition, Russia just agreed to send 50,000 tons of grain to North Korea and has invited Kim to make a state visit. Another diplomatic score for North Korea.
And South Korea just announced that it was sending almost $5 million in humanitarian aid via its' Red Cross to help the North deal with the damage caused by severe flooding. Kim again got what he wanted - not just the aid but also the fact that the South is allowing its' Red Cross to work with the North. That cooperation had been halted after last year's artillery fight.
In a case of interesting timing, yesterday the Asia News ran an article that said:
"The extended hand of the South Korean government to North Korea “is the last chance Pyongyang has to rebuild ties. If they fail this time as well, the conservative administration of President Lee Myung-bak will break off relations once and for all. And that will be the end, or war,” a source living near the border with North Korea told AsiaNews..."
Apparently Kim read the article as well and responded in his usual way. And the game just keeps going on and on and on...