The term "consensual hallucination" is Gibson's (from Neuromancer), who is generally credited with coining the term Cyberspace. "What seems so alluring about the half-formed promise of VR technologies is the ideal of a world of one's own that one can share with others through consensus but that one can enter or leave at will ... that brings with it a certain guarantee of pleasure without danger." (E. Grosz, Anybody)
Philip K. Dick's novel The Three Stigmata of Palmer Eldritch is a brilliant evocation of the pleasures and terrors of the idea of shared hallucinations: By using the drug CanD, the bored workers on mining colonies share a place of escape and reassurance by acting out traditional roles (Barbie and Ken). A new drug, produced by the villanous Palmer Eldritch, called ChewZ, leads to a place of persecution, where Palmer Eldritch enters directly into the hallucination. Thus the battles between the protagonist and villain are both real and hallucinatory, and during the course of the novel it becomes hopelessly unclear where they are taking place.
In contemporary electronic communities participants have "learned to delegate their agency to body-representatives that exist in an imaginary space contiguously with representatives of other individuals" Rosanne Stone's studies of phonesex and her role in the genderbending possibilities of cyberspace are particularly fascinating as Stone is a transsexual, in a state of " becoming woman" -- Deleuze and Guattari's expression for carrying the indeterminacy, movement , and paradox of the female stereotype past the point at which it is recuperable by the socius as it presently functions -- as a way to a rebecoming-super molecular of the personified individual. (Massumi. p87.)