As new technologies find new markets, the telecommunications field must deal with definitional problems and with challenges to existing regulation. This paper looks at the fields of cable television and telecomputing, and approaches to their regulation, in order to shed light on the question of telephone companies' (telcos) potential involvement in electronic publishing. Following an introductory section, the first section deals with the First Amendment and the media. The cable television monopoly is the topic of the second section; a third section discusses telecomputing. The telephone monopoly is treated in the fourth section, and the future of electronic publishing in the fifth. The conclusion asserts that telco exclusion from electronic publishing is no longer constitutional, and that telcos should be free to enter electronic publishing with any regulations on that freedom narrowly tailored to suit the specific threats telcos pose in the communications marketplace. Fifty-seven notes are included. (SR)