A crowd is a group of people that have gathered for a common purpose or intent. Examples are a demonstration, a sports event, or a looting (classified in sociology as an acting crowd). A crowd may also simply be made up of many people going about their business in a busy area.
The term "the crowd" may sometimes refer to the lower orders of people in general.
Crowd control is a public security practice in which large crowds are managed in order to prevent the outbreak of crowd crushes, affray, fights involving drunk and disorderly people or riots. Crowd crushes in particular can cause many hundreds of fatalities. Effective crowd management is about managing expected and unexpected crowd occurrences. Crowd control can involve privately hired security guards as well as police officers. Crowd control is often used at large, public gatherings like street fairs, music festivals, stadiums and public demonstrations. At some events, security guards and police use metal detectors and sniffer dogs to prevent weapons and drugs being brought into a venue.
Riot police are police who are organized, deployed, trained or equipped to confront crowds, protests or riots.
Riot police may be regular police officers who act in the role of riot police in particular situations, or they may be separate units organized within or in parallel to regular police forces. Riot police are used in a variety of different situations and purposes. They may be employed to control riots as their name suggests, to disperse or control crowds, to maintain public order or discourage criminality, or to protect people or property. The militarization of modern police has brought militaristic riot gear and new technologies that allow for their duties to expand above normal police duties.
The German noun Volk (German pronunciation: [fɔlk]) translates to people, both uncountable in the sense of people as in a crowd, and countable (plural Völker) in the sense of a people as in an ethnic group or nation (compare the English term folk).
Within an English-language context, the German word is of interest primarily for its use in German philosophy, as in Volksseele ("national soul"), and in German nationalism – notably the derived adjective völkisch ("national, ethnic").
Crowd psychology (or mob psychology) is a subfield of social psychology which examines how the psychology of a group of people differs from the psychology of any one person within the group. The study of crowd psychology looks into the actions and thought processes of both the individual members of the crowd and of the crowd as a collective social entity. The behavior of a crowd is much influenced by deindividuation (seen as a person's loss of responsibility) and by the person's impression of the universality of behavior, both of which conditions increase in magnitude with size of the crowd. Notable theorists in crowd psychology include Gustave Le Bon (1841-1931), Gabriel Tarde (1843-1904), and Sigmund Freud (1856-1939). Many of these theories are today tested or used to simulate crowd behaviors in normal or emergency situations. One of the main focuses in these simulation works aims to prevent crowd crushes and stampedes.
Crowdsourcing involves a large group of dispersed participants contributing or producing goods or services—including ideas, votes, micro-tasks, and finances—for payment or as volunteers. Contemporary crowdsourcing often involves digital platforms to attract and divide work between participants to achieve a cumulative result. Crowdsourcing is not limited to online activity, however, and there are various historical examples of crowdsourcing. The word crowdsourcing is a portmanteau of "crowd" and "outsourcing". In contrast to outsourcing, crowdsourcing usually involves less specific and more public groups of participants.
Advantages of using crowdsourcing include lowered costs, improved speed, improved quality, increased flexibility, and/or increased scalability of the work, as well as promoting diversity. Crowdsourcing methods include competitions, virtual labor markets, open online collaboration and data donation. Some forms of crowdsourcing, such as in "idea competitions" or "innovation contests" provide ways for organizations to learn beyond the "base of minds" provided by their employees (e.g. Lego Ideas). Commercial platforms, such as Amazon Mechanical Turk, match microtasks submitted by requesters to workers who perform them. Crowdsourcing is also used by nonprofit organizations to develop common goods, such as Wikipedia.