Developed by american documentary theorist, Bill Nichols. They include six different types of documentary ‘modes’: Poetic; Expository, Observational; Participatory; Reflective, Performative
When considering documentary modes, all documentaries can overlap into different modes. This is simply there to determine style and several aspects of documentary.
Content is the subject matter of any media production. The information we receive through interacting with media objects is content. The experiences, the visuals, the topics explored all this falls under content.
The style of any documentary is linked to the mode. If the film is observational (fly on the wall) then the style is going to be very free formed and often out of shot. Nothing will be staged or rehearsed, its simply being from the outside looking in.