It is helpful to have a general terminology for speaking of entropic communication. Already I have introduced the notions of source and sink. Note: I use the term ``sink'' only for inanimate recipients, as it sounds pejorative when applied to a human recipient.
The source must engage in a process I call ``extraction'' or sometimes ``production,'' in order to produce an entropic item for communication. The sink or recipient engages in a complementary process I call ``incorporation.'' After incorporation, we can say that the sink or recipient is in full possession of the item, that is, that the communication is complete.
We can, where appropriate, associate a monetary cost with each extraction and a monetary value with each incorporation.
Most communication is two-way. That is, the roles of the source and sink will reverse from time to time. However, especially when computers are involved, the entropic flow may be purely unidirectional: from a human to a computer, from a computer to a human, or from one computer to another.
Some communication is broadcast, that is, there are multiple recipients but a single source. Finally, a small amount of present-day communication is multicast, that is, there are multiple sources and recipients. A good example of multicast communication is the crowd noise at a football match.
Some apparent broadcasts and multicasts may be analysed accurately by considering all pairs of sources and recipients. When such pairwise analysis tends to obscure the important issues, I call these ``fundamentally broadcast'' or ``fundamentally multicast'' communications.