Katz and Lazarsfeld (1995)

Also known as the Multistep Flow Model is a theory which is based on a study of social influence which says that the media is unintentionally influenced by the "Opinion leaders". It says that most people receive the majority of their information secondhand through the influences of their "Opinion Leader". The "Opinion Leaders" interpret the media based on their own opinion then will communicate what they interpret to the individuals. That information will then be communicated through the general public who then become the "Opinion Followers".

An example of this I believe to be Newspapers, like The Sun. That newspaper will only communicate to the general public what they want them to know, which is influenced by their own opinions. Eventually the information from the newspaper is filtered through the general public and suddenly everybody is talking about what the newspaper has printed, which isn't necessarily factual.