Abstract: In a system for time-shifted viewing of television broadcasts, advertisements 41, 43 are provided with headers 50, 52 containing times of day at which that advert may be viewed or not viewed. A Personal Video Recorder (PVR) 60 stores adverts in an advertisement database 70, stores broadcast program segments in a program database 80, and broadcast rules in a rules database 90. For viewing of the program when time-shifted, the PVR checks the time of day, checks the headers of the adverts, and shows only adverts which are permissibly viewed at that time of day.