Norman Scott

Also you may want to add that members of the two sects have co-existed for centuries and share many fundamental beliefs and practices. But they differ in doctrine, ritual, law, theology and religious organization.Their leaders also often seem to be in competition. Many recent conflicts have emphasized the sectarian divide, tearing communities apart. “ A house devided”

I serve in the Arabic field and have studied the "final days" prophesies of Islam (and still need to do more). There is a difference between Shia branch and Sunni.   Iran (Shia) believe that they must invade Arabia because one of the final days battles will take place not far from Mecca. After this they will launch a major battle against Israel because the Dajjal (anti-Christ) will be a Jew.  This is leading to the wars and conflicts you see in the middle east between the various branches of Islam....(and the hate rhetoric between Iran and Israel). I have a suspicion it may escalate as we know that militarized/politicized religion is part of the sign of the end right before the destruction of false religion.   I see a lot of nasty war rhetoric coming from Iran as to how they want to annihilate Israel... this is all due to the final days prophesies of Shia Islam. 
The black flags and the calling of a caliphate in Iraq by IS - is part of final days prophesies of fundamental Sunni Islam.  Many who start being devout Muslims are taken in by this and want to go and fight there because they see it as a fulfillment of prophesy.  Doctors, lawyers etc go and fight for IS because of the prophesies.... It is not just the poor and disenfranchised who go and fight in Iraq for IS as touted by the media.
Additionally, most of these far-right crazy websites contribute to the confusion by further spreading exagerated reports BUT we know that the world will get embroiled in many conflicts (most religious by nature) before the final end. As long as we stay neutral in all of this and only trust in the salvation of Jehovah.