 A very early reference is the classic paper by Grossman and Stiglitz (1976) that showed that uninformed traders in a market context can become informed through the price in such a way that private information is aggregated correctly and efficiently.Subsequent work has shown that markets may systematically overweight public information; it has also studied the role of strategic trading as an obstacle to efficient information aggregation.Crowds that gather on behalf of a grievance can involve herding behavior that turns violent, particularly when confronted by an opposing ethnic or racial group.