FUD is an abbreviation for Fear, Uncertainty, and Doubt. Opponents of certain large computer corporations claim that the spreading of fear, uncertainty, and doubt is a marketing technique that these corporations consciously employ.
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 buyers 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. After 1990 the term has become generalized to refer to any kind of disinformation used as a competitive weapon.
The term is most frequently used in relation to Microsoft. The Halloween documents, leaked internal Microsoft documents whose provenance is not in doubt, use the term FUD to describe a potential tactic, as in "OSS is long-term credible ... FUD tactics can not be used to combat it." More recently, Microsoft has issued statements about the "viral nature" of the GNU General Public License (GPL), which are widely believed by computer industry observers to be attempts at spreading FUD. Microsoft's statements are often directed at the GNU/Linux community in particular, to discourage widespread Linux adoption, which could hurt Microsoft's marketshare.
By spreading (possibly untrue) information about the drawbacks of less well-known products, an established company can discourage decision-makers from choosing those products over its wares, regardless of the relative technical merits. This is a recognised phenomenon, epitomised by the belief of purchasing agents that nobody ever got fired for buying IBM equipment.
The result is that many companies' IT departments buy software which they know to be technically inferior because upper management is more likely to recognise the brand.
This article or an earlier version of it came from the Jargon File.