A method and system for auxiliary data detection. Data is received on a hand-held device from a display of a signal on a monitor. The signal is visually displayed on the monitor at a frequency. A modulated video signal is received on the hand-held device from a display device. The modulated video signal contains auxiliary data modulated within a video signal in a substantially invisible way. The modulated video signal is demodulated to obtain the auxiliary data. At least one of the data or the auxiliary data is processed to identify a promotional opportunity available through the hand-held device. The user of the hand-held device is notified of availability of the promotional opportunity through the hand-held device.