On a large public wiki, a wiki witchhunt is a wiki idiom for the attempt to discover or assert that several userids or IP numbers "are the same person" - a very low integrity attempt to define alleged and collective identity. See faction for a competent and civilized alternative.
According to Wikipedia founder Jimmy Wales, Wiki witchunts are not supposed occur.
To require response to hearsay is the most common first step. However, no one aware of group dynamics will answer to this consistently. This is then taken as validation.
Once vague attributions of the target are identified, the sysop power structure seeks to discourage them from contributing or challenging central control, by means of asserting some negative reputation, spreading libel, and further, using that as an excuse for ad hominem revert or even ad hominem delete or (most seriously) outing (applying some body name to what is effectively a group entity formed out of posts).
As an actual behaviour-shaping tactic, this rarely or never works: Genuine trolls seek such negative reputation as a sign of their prowess - in particular they seek to be extremely hated by inquisitors, since "the enemy of my enemy is my friend" and others who object to witch-hunts on principle will eventually find and offer direct help to the troll, thus making the wiki troll-friendly. Co-operating patrolls tend to work in pairs or more, and may actively cooperate to drive witch-hunters crazy and make them make wrong decisions. This is simple, as such hunters are already foolishly attempting to do amateur psychiatry without a license, and, already making wrong decisions almost by definition. On the Internet it is never easy to be sure of identity, with so many IP proxies and other people's text easy to retrieve and re-use.
There are many good examples, the vile mailing list being almost an historical record of same. We tend to discourage listing them, as that would only encourage inquisitors to seek out and punish those who make troll-friendly offers.
Like the actual witchhunt, this sad and petty (but not yet murderous) phenomena seems to be a symptom of dualism and groupthink. Many see the world in simple terms of friends and enemies, and believe that enemies of their enemies must be their friends. Sadly this requires everyone else to, as well, form factions (or looser troll organizations), note enemy projects that they have taken over. Since that alternate power structure can then respond with trolling tactics and other methods of wiki regime change, this tends to train others to employ the same tactics. A wiki vicious cycle ensures.
We basically hope it never happens here, but sadly our hopes have been dashed: supposedly-new trolls whose trolling displeases known trolls find themselves associated (against their will, some claim) with the Wikipedia power structure of inquisitors and sysop vandals. This is based admittedly on limited proof: amateur psychiatry and (more significant) the mindless repetition of known falsehoods like the already-discredited article on Craig Hubley that not even Wikipedia's quite low standards will admit. Also, it has not so far involved technological escalation, i.e. no IP blocks, so dialogue can continue: the newcomers can prove themselves to actually have New Troll point of view instead of the very old Sysop Vandal point of view which they dredge up out of old article histories and try to present as being fact.
Consumerium:Itself should eventually rely on factionally defined ways to seek out and assign editorial judgement to particular types of assertions, and rely on factions to approve or disapprove edits, so "who wrote this" is never an issue. In fact, that is pretty much the only way one can get identity out of the editorial decision.
We do not invite comment on Wikipedia policy except insofar as it degrades the GFDL corpus as a whole. Such issues in general should be discussed there not here! Almost all issues we can imagine that are relevant to wiki management and large public wikis have already been covered here, so, we don't need any more detail on that subject. Even the trolls are done ranting about it. For now!