A troll war is a situation that has escalated beyond flame war and edit war, both of which are tactics within it. It typically indicates a serious lack of judgement by more than one party, which renders it difficult to assign any blame or even determine the origins of falsehoods or any intent to lie - many assertions of various level of validity will fly around.
The most common "cause" of a troll war is a political or religious or sexual difference that gives rise to a heated debate, into which several participants of less than stellar judgement pour gasoline on the fires that are already smouldering in the debate. It becomes difficult to separate personality from factual from perspective/POV from reputation questions in such a situation.
Like what virtual community aficionados call a 'forest fire', typically the textual trail of such events will spread across many Talk: pages and mailing lists, and occupy far more attention than it is worth.
Further complicating the situation, often the participants will be capable of making stellar contributions in some narrow area, or represent some perspective that is under-represented, and the Wikipedia project will be loath to lose them. However they may be lost either due to frustration, libel, insult, or due to any official action, correctly directed or not, that discourages participation.
The recommended Wikipedia policy to deal with such a troll war is:
- document the events - IP numbers or IDs in use or seemingly in use, pages affected, timing
- determine whether one side or another is actually outmatched by technology or sheer volume of opponents - giving up due to pressure not due to veracity of arguments
- if so, equalize - wade in to neutralize statements by the technologically-enabled or more populated side, and go easy on those with only one IP or ID each, until the chaos subsides
- find a troll bridge that the more rational parties can start to work on
While doing these things, keep an eye open for any underlying political dispute that may be fueling the fire. If certain terms are in dispute, for instance, or being used pejoratively, this may suggest the right troll bridges to start with. For instance, one may suggest legally-defined or scientifically-defined terms rather than those politically or ideologically defined, so that terminology consensus can be built up.
See also: m:more heat than light