One primary use for events is changing properties of components in response to an event. The easiest way to implement this is with the Targeting > Tracking Sensors task area of the ACC. See Tracking Visitor Behavior in the ATG Personalization Guide for Business Users. The Personalization module implements tracking sensors through action handlers. An action handler component implements atg.service.event.ConfigurableActionHandler. Action handler components have an actions property that lists an array of the actions (atg.service.event.ConfigurableAction) to take in response to an event.