Text : Any media production; film/ advert etc.
Form: Category of media it is; book/film/advert/magazine/poster/ music video etc.
If a group of media texts have similar form/structure/pattern it might be due to a link in Genre (type/kind). They will share common structural elements to make them recognisable as a specific Genre. It represents a way of classifying popular cinema into distinct types - useful for splitting the audience into demographics.
Audiences often choose a film because they are a fan of the Genre. Investors run less risk when putting up money for a popular and well established genre. Genres can be further distinguished into Sub-Genres.
However, audiences may become tired of constant, repeated formats. To keep their interest, Genres can be blended and developed in new directions. These Genres are known as hybrids.