It's mostly the rarity value. Industrial accidents? No big whoop, happens a lot in the US. Car bombs and explosions? Happens a lot in Iraq. The actual body account is irrelevant, if we're talking social impact and media coverage. (Still not determined since no suspect, but assuming =Political) Bombings with intent to kill in crowded public areas are, let's face it, comparitively rare in the US and common in Iraq. That's why this is news. Same reason 9/11 was so "shocking". Looked at objectively it was really small scale destruction. But it happened in area not known for all-out destruction, so novelty value kicked in.