Research has picked out three main strategic areas for protest control, favored differently by the police in various historical periods (della Porta and Reiter 1998a): coercive strategies, i.e. use of weapons and physical force to control or disperse demonstration; persuasive strategies, meaning all attempts to control protest through prior contacts with activists and organizers; informative strategies, consisting in widespread information-gathering as a preventive feature in protest control; and the targeted collection of information, including use of modern audiovisual technologies, to identify law-breakers without having to intervene directly