1. A method of modulating operation of a device, comprising: disposing a hardware sensor in or on the device for sensing attention of a user specifically toward the device; processing a signal from the hardware sensor and outputting to the device a measure or index of the user's attention toward the device; and modulating operation of the device on the basis of the measure or index of the user's attention toward the device; wherein the operation that is modulated is initiated by the device and provides a notification and/or information and/or communication to the user based on the user's attention toward the device.