The Jargon File (version 4.4.7, 29 Dec 2003):

backbone cabal
 n.

    A group of large-site administrators who pushed through the Great Renaming
     and reined in the chaos of Usenet during most of the 1980s. During most
    of its lifetime, the Cabal (as it was sometimes capitalized) steadfastly
    denied its own existence; it was almost obligatory for anyone privy to
    their secrets to respond ?There is no Cabal? whenever the existence or
    activities of the group were speculated on in public.

    The result of this policy was an attractive aura of mystery. Even a decade
    after the cabal mailing list disbanded in late 1988 following a bitter
    internal catfight, many people believed (or claimed to believe) that it had
    not actually disbanded but only gone deeper underground with its power
    intact.

    This belief became a model for various paranoid theories about various
    Cabals with dark nefarious objectives beginning with taking over the Usenet
    or Internet. These paranoias were later satirized in ways that took on a
    life of their own. See Eric Conspiracy for one example. Part of the
    background for this kind of humor is that many hackers cultivate a fondness
    for conspiracy theory considered as a kind of surrealist art; see the
    bibliography entry on Illuminatus! for the novel that launched this trend.

    See NANA for the subsequent history of ?the Cabal?.


The Free On-line Dictionary of Computing (30 December 2018):

backbone cabal

    A group of large-site administrators who pushed
   through the Great Renaming and reined in the chaos of
   Usenet during most of the 1980s.  The cabal mailing list
   disbanded in late 1988 after a bitter internal cat-fight.

   [Jargon File]

   (1994-11-28)