The Bush administration took North Korea off that list as a concession, and Obama has not seen fit to put them back on despite things like the bombing of
Four people, including two civilians, were killed when North Korea launched bombs against Yŏnpyŏng-do, an island in the Yellow Sea, one of the isolated "Five Islands of the West Sea" that sit close to the North Korean mainland.
I myself am on the fence about this. I think that moving them to the terrorism sponsor list again should only be done for something very serious, and perhaps those past military acts were serious enough, but I think we ought to wait until a time when such a move is part of a strategic overall plan to punish them for something they've done recently. In other words, the moment has passed for that, and we should use the threat of putting them back on the list as a way of getting them to behave right now.