Bernhard Siegert hypothesizes a "postal epoch," in which "communications were transmitted directly from one individual to another" (Kienle's summation)
which has given way to an era defined by a "circuit processing an undifferentiated volume of printed matter" (Siegert's phrasing)
see Siegert's Relays and Colby Chamberlain's piece on "George Maciunas and the Mail," which interprets Fluxus through Siegert's formulation