Defined by Gene Amdahl after he left IBM to found his own company:
FUD is the fear, uncertainty, and doubt that IBM sales people
instill in the minds of potential customers who might be considering
[Amdahl] products.
The idea, of course, was to persuade them to go
with safe IBM gear rather than with competitors' equipment. This implicit
coercion was traditionally accomplished by promising that Good Things would
happen to people who stuck with IBM, but Dark Shadows loomed over the
future of competitors' equipment or software. See
IBM. After 1990 the term FUD was associated
increasingly frequently with Microsoft, and has
become generalized to refer to any kind of disinformation used as a
competitive weapon.