The Columbia Broadcasting System had its roots in early radio broadcasting, via the Chicago-based United Independent Broadcasters network, which went on the air in 1927. In those days, it made sense for radio broadcasting to be linked to the music industry. When the UIB network was purchased by the owner of Columbia Records in 1928, the broadcast network was renamed the Columbia Broadcasting System, a name that was officially shortened to CBS, Inc. in 1974. Together with ABC and NBC, CBS was one of the "Big Three" American broadcast networks. The trio of companies virtually controlled commercial television in America for most of the twentieth century.
CBS, which had gained the nickname "the Tiffany Network" in reference to the perceived quality of its programming, had the reputation through much of its reign among the Big Three as appealing primarily to a relatively older audience than its competitors. CBS periodically attempted to shift that reputation, and in the 1970s the network produced a number of hit shows-The Mary Tyler Moore Show, All in the Family and M*A*S*H among them-that managed to capture the attention of a younger demographic. In the 1980s, CBS remained a popular network, although many of its hit series-Murder, She Wrote; Dr. Quinn, Medicine Woman; Diagnosis: Murder, etc.-were once again attractive mostly to older viewers.
Like the other broadcast networks, CBS has developed a presence on the internet in order to cope with the shifting demands of viewers and the decreased influence of broadcast television.