Abstract: A method for distribution of information includes displaying a sequence of promotional images at known, respective display times on a display terminal facing customers at a point of sale. Sales of different products at respective sale times are recorded on a sales terminal at the point of sale. A relationship between the sales times of at least one of the products and the display times of at least one of the promotional images is measured. Responsively to the relationship, a change is made in the sequence of the promotional images that are displayed on the display terminal.

Abstract: A computer-implemented method for data display is provided, which includes receiving a request for a product from a customer in a first line at a retail location having multiple adjacent customer lines. An advertisement is selected responsively to the requested product, and is displayed on a customer-facing electronic display positioned at a second line, which is in proximity to the first line. Other embodiments are also described.

Abstract: A method for distribution of information includes displaying a sequence of promotional images at known, respective display times on a display terminal facing customers at a point of sale. Sales of different products at respective sale times are recorded on a sales terminal at the point of sale. A relationship between the sales times of at least one of the products and the display times of at least one of the promotional images is measured. Responsively to the relationship, a change is made in the sequence of the promotional images that are displayed on the display terminal.

Abstract: A computer-implemented method for data display is provided, which includes receiving a request for a product from a customer in a first line at a retail location having multiple adjacent customer lines. An advertisement is selected responsively to the requested product, and is displayed on a customer-facing electronic display positioned at a second line, which is in proximity to the first line. Other embodiments are also described.

Abstract: A method for generating an audio output from an audio amplifier, the method consisting of receiving a segment of an input audio data stream into a buffer, identifying an adjustment interval in the segment, and calculating an average energy of at least a section of the audio data in the buffer subsequent to the adjustment interval in the segment. The method further includes determining a constant amplification factor in response to the average energy and to a pre-set volume level of the audio output, outputting the audio data from the buffer to the audio amplifier, and, when the audio data output to the audio amplifier reaches the adjustment interval, adjusting the audio amplifier to apply the amplification factor to the audio data in at least the section subsequent to the adjustment interval.