The models in this group are the largest body of theory in the subject, and most of them answer one question: what shapes a message between the world and the person who finally hears about it? They disagree sharply about the answer. That disagreement, more than any single model, is what the group has to teach.
Four places to look
The first family places the shaping in people with power over the flow. Gatekeeping puts it in editors and producers deciding what runs. Agenda-Setting Theory adds that media set which issues people think about, and its second level adds which features of those issues seem to matter. The Two-Step Flow moves the influence down a level, to opinion leaders who interpret media for the people around them. The Propaganda Model and Concision move it up, to ownership, advertising, sourcing and the constraints of broadcast format.
The second family places it in the medium itself. McLuhan's claim that the medium is the message, the broader media ecology tradition, the Attention Economy and Context Collapse all argue that the form of a channel matters more than what travels through it. Context collapse is the most practical of them: the same post now reaches audiences who once heard separate versions, and no single register suits them all.
The third family places meaning with the receiver and the culture around them. Speech Act Theory shows that some utterances do things rather than describe them. The Death of the Author and the Semiosphere hand interpretation to readers and their culture. Taarof and Vranyo, from Persian and Russian practice, show whole conversations in which nobody means the words literally and everyone knows it. The Dog Whistle is the adversarial version: a message built to mean different things to different listeners.
The fourth family treats communication as conflict between sides. Arguments as Soldiers, the Spiral of Silence and the Toxoplasma of Rage describe what happens when positions become identities: concessions look like betrayals, minority views go quiet, and the least defensible cases travel furthest because they provoke the most argument.
Where the models are used
Campaigns use them constantly, whether they cite them or not. Deciding to win over local figures rather than buy national advertising is two-step flow in practice. Choosing which issue to talk about, rather than what to say about it, is agenda-setting. Organisations meet context collapse every time a message to one group is forwarded to another. Anyone doing business across cultures meets taarof or its equivalents, and the cost of reading a ritual refusal literally.
The models are also the vocabulary of media criticism, and a reader who knows several of them can see which one a critic is using. A complaint that a newspaper ignored a story is a gatekeeping complaint. A complaint that it covered the story in a way that favoured one side is closer to the Propaganda Model or its mirror images.
Where the group is argued over
This is the most politically contested group in the subject, and the contest runs in both directions. The Propaganda Model and Concision come from the left and locate bias in commercial ownership. Anton's coinages, from the Celebration Parallax to the Lie-Back Imperative, come from the right and locate it in the conduct of a cultural elite. The ledger files both, each with its supporters' case and its critics' case, and the entries show that each side's model is weakest in the same place: it is easier to apply to opponents than to test.
The empirical disputes run separately. Cultivation theory's effects are smaller in later work than its founders claimed. The Filter Bubble is real as a mechanism, but studies of actual news diets find them more varied than the theory predicts. McLuhan's claims resist testing altogether, which his admirers treat as depth and his critics as the problem.
Why it is worth knowing
No single model here is right about everything, and several contradict each other. Their value is as a set of places to look. When a message arrives distorted, the question is which filter did it: an editor, an owner, a format, a peer, a culture, or the reader's own side. Knowing the models turns a vague sense that something is off into a specific hypothesis that can be checked, and it makes it harder to reach for the one explanation that happens to blame the other side.
The entries behind this essay: Model in Communication & Media. Every subject has its essays on the essays page.