pseudo: /soo'doh/ [USENET: truncation of `pseudonym'] n.

:pseudo: /soo'doh/ [USENET: truncation of `pseudonym'] n. 1. An
electronic-mail or {USENET} persona adopted by a human for
amusement value or as a means of avoiding negative repercussions of
one's net.behavior; a `nom de USENET', often associated with
forged postings designed to conceal message origins. Perhaps the
best-known and funniest hoax of this type is {BIFF}.
2. Notionally, a {flamage}-generating AI program simulating a
USENET user. Many flamers have been accused of actually being such
entities, despite the fact that no AI program of the required
sophistication yet exists. However, in 1989 there was a famous
series of forged postings that used a phrase-frequency-based
travesty generator to simulate the styles of several well-known
flamers; it was based on large samples of their back postings
(compare {Dissociated Press}). A significant number of people
were fooled by the forgeries, and the debate over their
authenticity was settled only when the perpetrator came forward to
publicly admit the hoax.
-- The AI Hackers Dictionary