The document discusses the effectiveness of combining a main horror film product with supporting ancillary texts such as a trailer, poster, and magazine cover. It argues that these ancillary texts are a good combination with the main product because they follow horror genre conventions. It also claims that effective ancillary texts can help promote the film, draw more viewers, and allow potential audiences to get a sense of the film before its release. This combination of high quality main product and ancillary texts is believed to positively impact the film's box office success.