A method of calculating feedback parameters for presentation images presented to spectators, comprising obtaining a presentation stream comprising a sequence of a plurality of presentation images, analyzing the presentation stream to identify a plurality of presentation periods of a presentation session, during each presentation period an associated one of the plurality of presentation images is presented to one or more spectators, receiving a plurality of feedback messages transmitted by client device(s) used by the spectator(s) to provide feedback to one or more of the presentation images, correlating each feedback message with one of the presentation images according to a presentation period during which the feedback message is received and transmitting the correlated feedback messages to feedback analysis system(s) adapted to calculate one or more feedback parameters for one or more presentation images based on the feedback extracted from the feedback messages correlated with one or more of the presentation images.