Abstract: In an example of an embodiment of the invention, data relating to at least one impression of at least one person with respect to a display is detected, and a party associated with the display is charged an amount based at least in part on the data. The at least one impression may include an action of the person with respect to the display. The action may comprise a gaze, for example, and the method may comprise detecting the gaze of the person directed toward the display. The person's gaze may be detected by a sensor, for example, which may comprise a video camera. An invoice may be generated based at least in part on the data, and sent to a selected party. The display may comprise one or more advertisements, for example. A face monitoring update method is also disclosed. Systems are also disclosed.