From "Organizations" (March and Simon):

Not only are organizational communications characteristically specific with respect to the channels they follow, but they also exhibit a high degree of specificity with respect to content. Here there is a strong contrast between organizational communications and communications through mass media. The audiences to whom newspapers and radio address themselves possess no common technical vocabulary; there is no subject about which they have any shared special knowledge; there is no good way of predicting what they will be thinking about when the mass communication reaches then. In principle at least, the recipient of an organizational communication is at the opposite pole. A great deal is known about his special abilities and characteristics. This knowledge is gained from considerable past experience with him and from a detailed knowledge of the work environment in which he operates.