Methods of operating a communications system comprise, in one example, inserting advertising in a program stream by a receiving device based, at least in part, on an encrypted segmentation message embedded in the program steam. The at least one segmentation message defines an expanse of the program stream to receive the advertising. At least one embedded decoy message is included in the program stream, as well. In one example the receiving device, which may be a set-top terminal, for example, is coupled to a display device, such as a television, at a user location. A method of operating a receiving device coupled to a display device at a user location is also disclosed, comprising programming the receiving device to record a program and recording the program based, at least in part, on at least one segmentation message in a program stream. Systems are disclosed, as well.