You know, it find it sort of curious, that 100 years after the event, we are still trying to determine who was to blame... and still fall back on nation-calling. Seems like we all have not learned that much.
The underlying causes of the great war were present in all of the european states. Rabid capitalism, elitism, imperialism, and -uhem- nationalism. In all of them, it was easy for the ruling ´class´, or elite, to sway masses of suffering quasi-servitutes into becoming willing (at first) cannon-fodder. It´s amazing, how they managed to arm millions and have them shoot each other, instead of those who told them do so. It´s stunning to see warbond after warbond getting oversigned. Every one of the signataries is to blame for the war. Everyone who thought to profit from it. Everyone who was not willing to make a sacrifice to prevent or to stop it. It was a mass-failure of humanity on a continental scale and we should inquire, which conditions could make this possible, cause these are to blame - and not so much which nation was the worst governed at the time (it clearly was germany, well, although russia and austria and serbia... well...), so that its ruling class did manage to veil its ambitions with rightousness.
Edit: And i daresay, that our socities have not changed all that much since then. Sure, the world has. There wouldnt be another european war like that. Europe is economically way to interlocked these days. But on a global scale, i think the same pattern could very well repeat. It´s not like our newspapers or TVs were truely neutral, they constantly try to sway us. You know, like i really cared enough for gay people in russia to her about it every second day. Russia, Iran and China get their fair amount of bashing on a constant basis. Ay-wei-wei. Like I f* care for a chinese artist. Sorry. But i know, it´s not about him.