An alert network is described. The alert network has a plurality of individual monitoring systems, a plurality of user terminals respectively associated with the individual monitoring systems, alert transmitters in the monitoring systems, for transmitting primary alerts to selected user terminals and/or to other monitoring systems in accordance with parameterized transmission rules, alert receivers in said terminals, and alert propagators in the terminals, capable of selectively propagating received primary alerts to other terminals and or to other monitoring systems as secondary alerts, in accordance with parameterized propagation rules. A method for transmitting and propagating alerts according to corresponding parameters in such a network is also described.