Sherry Turkle's most recent book, *Life on the Screen* contains something of a report on a dead medium which has been mentioned before on this list: the French (Parisian) system of pneumatic tubes for letter delivery.
What I find interesting about this is (a) the recency of the report == Turkle lived in Paris in the early 60s; and (b) the specific use for which this medium retained its relevance:
"I stayed with a family [in Paris] who avoided the telephone for everything but emergency communications. An intimate communication would go by *pneumatique.* One brought (or had delivered) a handwritten message to the local post office. There, it was placed in a cannister and sent through a series of underground tubes to another post office. It would then be hand delivered to its destination.
"I was taught that the *pneumatique* was the favored medium for love letters, significant apologies, or requests for an important meeting. Although mediated by significant amounts of technology, the handwritten *pneumatique* bore the trace of the physical body of the person who sent it; it was physically taken from that person's hand and put into the hand of the person to whom it was sent. The pneumatique's insistence on physical presence may have ill-prepared me for the lessons of postmodernism, but it has made e-mail seem oddly natural."
As we delve into the reasons for a medium's death or disappearance, it would be wise to keep in mind those media which deliver this sense of physical presence and see if that (or something like it) is a factor in media Darwinism.
Alan Wexelblat moderator, rec.arts.sf.reviews
MIT Media Lab - Intelligent Agents Group