The two-step flow of communication

This model by Lazarsfeld and Katz hypothesizes that ideas flow from mass media to opinion leaders, and from them to a wider population.
Personal influence came to illustrate the process intervening between the media's direct message and the audience's reaction to that message. For example, the James Bulgar case; a boy told his friend about a film he had watched and influenced the other's behaviour.
The two-step theory refined the ability to predict how media messages influence audience behaviour and explains why certain media campaigns do not alter audiences' attitudes.
However, the hypothesis has been critised by myriad consequent studies, saying they find substantial evidence that initial mass media information flows directly to people on the whole and is not relayed by opinion leaders.

Audience theory

According to Barker and Petley, there is an obsession with trying to prove that the media are responsible for a range of social problems, and the researchers who want to find this link carry on despite the lack of evidence to support the idea.
The hyperdermic syringe theory is that the media is like a syringe which injects ideas, attitudes and beliefs into the audience. However, this is largely rejected today.
Uses and gratifications theory is more about what people do with the media to satisfy various individual and social needs that we have. Criticisms of this theory is that you may be a secondary user and you can't always chose what media you use. For example, you have no control over what advertisements get shown on television.

Borrowed Interest

Borrowed Interest is the intentional association of an unrelated theme or image with the product. On the television programme The X Factor, they are not allowed to do this. The judges may have drinks on the judging table, but they must take the label off of the bottle so it doesn't advertise or draw attention to the company. A product that includes borrowed interest, is Rihanna's music video 'Man Down'. In the video, she drinks a coconut water called 'Vita Coco' which obviously promotes the company as she is a famous, iconic role model.

Intertextuality

Intertextuality is the shaping of texts' meanings by other texts. For example, many films have aspects found in The Matrix. Such as Shrek, which contains the famous slow-motion fight. Texts like Alice In Wonderland  have references to the rabbit hole, and being offered a magical key to another dimension of reality. Many of the actual concepts on The Matrix came from comic books, anime art work and there might even be a direct copying of a Doctor Who episode where the doctor fights the master of gallifrey, in a digital universe called The Matrix.
Some texts deliberately play with intertextuality, teasing the audience to spot the references; this has been called one of the codes and conventions of a post-modern text. For example, The Simpsons.

Auteur Theory
Auteur Theory suggests that the best films will bear their maker’s ‘signature’.  Which may manifest itself as the stamp of his or her individual personality or perhaps even focus on recurring themes within the body of work. Alfred Hitchcock plays this idea up in most of his movies where he makes sure that he appears on screen in a brief cameo spot. This became a game that viewers would engage in, waiting to find out when he would appear. One of the themes Hitchcock used are extreme close-ups. This theme has diminished from thriller/horror genres over the years as it can be seen as comical.
One of the problems with auteur theory is that it tends to diminish the role that others play in the creation of a film. Hitchcock himself downplayed the role that others played in his films. He was often critical of his actors and usually did not give his screenwriters the recognition that they deserved.

Semiology

Semiology is an approach that can be used to understand how media texts make meaning for their audiences. This includes denotations, connotations, context and anchorage.

Denotations (literal meanings): Yellow background, a woman and a man looking at eachother, the man is smoking.
Connotations (associations): The man is blowing smoke in the woman's face on purpose- he is in control, they may be in a sexual relationship, he's tormenting her.
Original caption: "Blow in her face and she'll follow you anywhere".
This old advert for cigars shows sexist undertones; we might not have noticed this without the underlying meaning and caption.
Other captions showing different meanings:
Man: "Don't you like me smoking?"
Woman: "You're standing on my toe."