A server receives a source signal stream having a channel identifier and an indication that an advertisement placement opportunity is located in the signal stream a time period prior to an advertisement signal point. The server transmits the channel identifier to a session manager. The server receives from the session manager a list of sessions corresponding to a number of recipients currently viewing a channel corresponding to the channel identifier. The server transmits to an ad decision service an ad call for each session in the list. The server receives from the ad decision service a plurality of advertisements targeted to the list. The server stores the plurality of advertisements in at least one cache prior to expiration of the time period, where the advertisement signal point is detected by the programmed computer.