I'm following news of the Norway attacks like the rest of you, and am curious to see, among other things, Norway's response. I hope it is not to pull troops out of Afghanistan; this would only breed more attacks. So, why Norway? It doesn't seem likely, on the surface, if this is jihadist in origin. There are many countries with more troops in Afghanistan than Norway; and there are several countries whose newspapers have printed cartoons of the Prophet Muhammad. My first reaction is two-fold: 1) Jihadists did this in Norway because they could. Norway is pretty well-known among homeland-security types for being among the softer, less-defended countries of the West, and 2) Norway is making moves to expel a jihadist called Mullah Krekar, who is one of the founders of Ansar al-Islam, the al Qaeda-affiliated group that operated in Iraqi Kurdistan with some help from Saddam's intelligence services. This could be a message about his coming deportation.
Of course, asking the question, "Why did jihadists attack (x)?" could lead people to believe that these sorts of attacks are responses to particular events. They are not. At the deepest level, they are responses to Western existence. I know that this sort of statement sounds too Bushian for some people, but I tend to think that many hardcore jihadists -- i.e. ones who are willing to murder innocent people -- develop a deep desire to murder infidels, and only then go looking for specific places to do this murder, and only then gin-up weak rationalizations for the murder. In other words, the list of ostensible grievances is endless.