Here are some ways messages can be communicated from person to person: speaking; in a book; by Instant Message; on the www; email; television; geography. How do these differ? Ignoring what sort of encoding these different media types contain (the book contains the written word), consider just the nature of the medium.
So you see I'm trying to understand what the differences in media are, starting by trying to identify different properties. Firstly, I need a need a word. There's a point of no return for a message, beyond which it's in my brain and understood, a helter-skelter from just after my ears and just inside my eyes to my mental processing centres. It isn't understanding, and it isn't hearing, it's the process of internalising.
Secondly I'm wondering whether all these properties can be expressed in terms of abstraction points. Between the message being internal to person A and being internal to person B, at what points can it be deflected, edited, duplicated, referenced, delayed? In speaking this abstraction point is used once, sound allows a certain kind of broadcast, but that's it. With other media types it's more varied.
Tele has two big points. Initially the message is constructed outside the brain before being transmitted, so many people can work on it. Secondly, a piece of equipment called a television set acts as a proxy for you (and your household), an ear into electromagnetic sounds and pictures, to negate distance. This dimension doesn't have the concept of distance which means that the broadcast tower and all television sets effectively exist at the same point, inside a singularity, so the broadcast can't discriminate between different sets. It does however have the concept of direction, so transmission is one-way.
Geography (and the www) is interesting. A reference to a location can be spread and communicated independently of the location itself. There are even map shops! And that place (or website) can change all the time. Dereferencing the map or the url can reveal a constantly changing database driven 'site, or a geocache.