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

Datamation
 /day`t@?may'sh@n/, n.

    A magazine that many hackers assume all suits read. Used to question an
    unbelieved quote, as in ?Did you read that in Datamation??. It used to
    publish something hackishly funny every once in a while, like the original
    paper on COME FROM in 1973, and Ed Post's Real Programmers Don't Use
    Pascal ten years later, but for a long time after that it was much more
    exclusively suit-oriented and boring. Following a change of editorship in
    1994, Datamation briefly tried for more the technical content and
    irreverent humor that marked its early days, but this did not last.


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

Datamation

   /day"t*-may"sh*n/ A magazine that many hackers assume all
   suits read.  Used to question an unbelieved quote, as in
   "Did you read that in "Datamation?""  It used to publish
   something hackishly funny every once in a while, like the
   original paper on COME FROM in 1973, and Ed Post's "Real
   Programmers Don't Use Pascal" ten years later, but it has
   since become much more exclusively suit-oriented and boring.

   [Jargon File]