1. A system for estimating the audience size of a digital broadcast transmission comprising: at the transmitting side, control means for maintaining an audience estimate and placing the audience estimate and a control number into a control packet and producing a flow of control packets to be multiplexed with a media stream; at the receiving side, means for processing control packets; a random number generator coupled with the means for processing control packets for obtaining the audience estimate placed in the control packet and generating a random number within a range of numbers wherein the range is a function of the audience estimate; response means coupled with the means for processing control packets for obtaining the control number placed in the control packet and further coupled with the random number generator for obtaining the generated number, the response means being operative for sending a notification back to the transmitting side over a return path if and only if the generated number is equal to the control number; and at the transmitting side, monitoring means coupled with the return path for counting notifications sent by all receivers and comparing actual counts with count statistics theoretically predicted for correct estimates, the monitoring means further being coupled with the control means for increasing the audience estimate placed in the control packet if the actual counts are statistically greater than theoretically predicted or decreasing the audience estimate if the actual counts are statistically lesser than predicted until the actual counts become as predicted; thereby reducing the volume of audience data transmitted from the receivers over the return path and keeping the volume independent from the audience size that, in turn, prevents the return pass capacity overload and provides an accurate measurement of any audience no matter how large or small it is.