Dr Clam said
As for modus operandi, blowing up people with bloody great bombs in Beirut is pretty much par for the course for Iran, viz. the 1983 truck bombing of the US Marines.
I heard once in a crime show(Law and Order Criminal intent) that you can copy someones MO, but you can't copy their "signature". I don't quite think this particular strike has the hallmarks of the Iranian secret service. I would have thought that they would rely on suicide bombers within the sphere of Lebanon. Also(on the motive side) the noises I am hearing from Iran seem to still be to find common cause against Israel rather than what you are suggesting to break ranks with Syria. Their motives by my game theory reckoning is still for untraceable support for attacks against Israeli, western and democratic targets opportunistically (in that order), rather than an attack which seemed the target was more important than the timing, and that the target didn't fit the "enemy of Islam" criteria particularly well. In my quick flip through various net sources, I found an Iranian one that claimed that it was the work of Israel or US, based on the political leverage they have both gained.
If you want to know, "the Economist" made a quick comment regarding the mysterious circumstances, but ever since they've been gushing over how the feeling on the "Arab street" has seemed to change for the better in such a short time.