It's a Small, Virtual WorldConfusion on Infinite (Virtual) WorldsIt's a Small, Virtual World - RSS 2.0
This is part of the fun of expanded-universe experiences, spotting the things that slip from one into the other - like the Star Wars comic-book character Quinlan Vos who made it into Revenge of the Sith via name-drop, or the two-episode guest character on Star Trek who became prominent in the New Frontier series of spin-off novels. For the audience that caught the Millennium Falcon's cameo in Revenge of the Sith, it's the thrill of discovering "winning" data in a mess of background noise. It's like finding Waldo.
Alvin Toffler, the futurist, told us this would happen. He predicted that post-industrial societies would fragment into numerous subcultures based on their own niche lifestyles. He was right. Some of those subcultures' lifestyles are lived on virtual worlds orbiting television series like suns.
These virtual worlds are facilitated by the internet, but they are not virtual in the sense that they are computer-rendered digital environments. These are analog networks, human networks, transmitting and receiving new stories and episodes that contribute to virtual worlds stored on multiple human servers and accessed through writing, play-acting, cosplay and other "prosumer" acts.
New content, some of it pretty and some of it nasty, is being created all the time. Someone just now has written new slash-fic about the cast of Bones. Someone else just self-published a really beautiful piece of poetry that you won't take seriously because it's written from the POV of some character on One Tree Hill. To the writers and fans of that material, it may widen the virtual world they share, in the shadow of the seminal work. Whether you absorb it into your instance of the show's virtual world or not, it all goes into one vast cosmos of possible worlds - the show's potential expanded universe.
This isn't new. The same, millennia-old critical problems that Aristotle wrote about in Poetics are prime issues for the audiences of expanded universes and virtual worlds rendered in an audience's pop consciousness. Aristotle wanted to measure and compare the values of poetry by gauging how well the poet represented the gods. Those gods were the seminal works, the cultural touchstones with which all the fans were assumed to be familiar. They were the official canon.
By addressing critical problems, Aristotle was, in a way, evaluating whether new works should be rejected or accepted into the expanded universe of the cosmology through popular consensus (driven by his expert opinion).
The most obvious of Aristotle's critical problems - "The thing represented is impossible" - is the equator which divides the two hemispheres of any expanded universe: canon and what-if. This is the critical problem hunted by the encyclopedic nerd who cites episode and scene as chapter and verse. ("But Picard couldn't have been there for that battle, 'cause in Episode 211 he said he'd never been to that planet!") If a work in the expanded universe can't agree with canon, it must be pushed across the equator, making it a what-if piece. Often, the only way for a piece to move from what-if into canon is through ret-conning.