A French grocery chain learned the hard way about marketing to a mob. It started a mad rush for Nutella, the chocolate and hazelnut spread. The riots were caused by a deep discount for the product. Frenchmen lined up at the doors of the grocer then rushed for the bottles. There was fighting. There was damage. There were futile efforts for crowd control. The promotion can be deemed a success, but not one the grocer would try again anytime soon. It clearly had no intimation of demand for the product when it slashed prices. It does now.