Concept that could use further discussion

A concept that I personally feel could use further discussion I would have to say would be with Mass Communication in chapter 11. The reason I say this is because to me it seemed too complex, there were some parts I didn't understand when it came to the institutional sources, invisible receiver, and interposed channel. As I read the background on each concept I was still unsure as to what it meant. I thinks perhaps a straight forward definition would suffice. I understand what Mass Media is in general I don't however really understand how this ties into the realm of Mass Media