"Ochlocracy (Greek: οχλοκρατία or okhlokratía; Latin: ochlocratia) is government by mob or a mass of people, or the intimidation of constitutional authorities. In English, the word mobocracy is sometimes used as a synonym. As a pejorative for majoritarianism, it's akin to the Latin phrase mobile vulgus meaning "the easily moveable crowd," from which the term "mob" originally derives." "In ancient Greek political thought ochlocracy was considered as one of the three "bad" forms of government (tyranny, oligarchy and ochlocracy) as opposed to the three "good" forms of government (monarchy, aristocracy and democracy). The distinction between "good" and "bad" was made according to whether the government form would act in the interest of the whole community ("good") or special interests ("bad")." "Whether or not the decisions enforced by a mob are good or bad is another matter entirely. The threat of mob rule (not unlike the term tyranny of the majority) is often invoked -often rhetorically- against a democracy by those who oppose its majoritary decisions, sometimes fearing oppression of the needs or freedoms of minorities if democratic government is not efficiently restrained by protections given to individuals under the rule of law, sometimes concerned that demagogery may manipulate the mob and force popular currents of thought onto minority groups without respect for their or the individual's rights. There are also some who wish to see more power assigned to a certain ruling minority. A mob, however massive, and regardless of claims to speak for 'the people', may or may not be representative of the (often silent) majority in a large society (which usually practices indirect democracy). It may be composed of a specific segment of the population interested in a specific issue, and drawn from a limited geographical space or it may be a representative popular majority." Source and further information: http://en.wikipedia.org/wiki/Ochlocracy

There are no pros to mobocracy. Whenever an emotional mob takes control, innocent individuals lose their rights and get trampled on.