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

Halloween Documents
 n.

    A pair of Microsoft internal strategy memoranda leaked to ESR in late 1998
    that confirmed everybody's paranoia about the current Evil Empire. These
    documents praised the technical excellence of Linux and outlined a
    counterstrategy of attempting to lock in customers by ?de-commoditizing?
    Internet protocols and services. They were extensively cited on the
    Internet and in the press and proved so embarrassing that Microsoft PR
    barely said a word in public for six months afterwards.