The first question that arises when contemplating fandom is a rather basic one: what is fandom? It's a complicated question, because it means different things in different contexts. But let's start with the most basic definition: a fandom is the entire body of fans of some particular thing, like Buffy the Vampire Slayer or Phantom of the Opera or Harry Potter. And I do mean the entire body: not just the Big Name Fans like (to use Harry Potter fandom as an example) Melissa Anelli or Steve Vander Ark, but also this woman and the lady at my church who discusses Harry Potter with, as far as I know, me and no one else. Fandoms are, in other words, enormously large, possibly unimaginably so in the case of Harry Potter.
(Fandom is also used to describe the entire online fandom community, as in the popular community Fandom Wank. Fandom Wank isn't dedicated to any one fandom, but to all of them. As I type this, there are posts on the front page of the community about Harry Potter fandom, House fandom, comic book fandom, World of Warcraft fandom, and Richard Hammond fandom, whoever the hell Richard Hammond is. In the eyes of Fandom Wank, all fandoms are as one. And to some degree, I agree with them. But I digress.)
When most people talk about fandom, they're talking about one particular aspect of organized fandom, groups of fans that coalesce around a certain point, like LiveJournal or TWoP or Usenet. These organized fandoms can be pretty darn big in their own right, and there's a certain cross-pollination among them -- petzipellepingo, for example, is active in both the TWoP Buffy fandom and the LJ Buffy fandom -- but it's possible for two people to be active in fandom without ever crossing paths, simply because they're part of different sub-fandoms. Like, for example, me and Allyson Beatrice. I was never as active in Buffy fandom as Beatrice, but back in the day I was, I think, a fairly unavoidable presence in the TWoP Buffy forums. Meanwhile, Beatrice was posting up a storm in the Bronze at buffy.com, the Buffy threads at salon.com's Table Talk, and finally at buffistas.org. But until she wrote her book and I read it, our paths never crossed.
Which is why I had a little chuckle when I read Beatrice say of herself, "I [was] deeply entrenched in the Buffy and Angel fandoms for years and everyone who actively participated in those online fandoms knew [me] and trusted [me]." Now, perhaps I was, in fact, the only person in all of online fandom who didn't know Allyson Beatrice. My fault, really; glumpish knows her, and if I'd ever bothered to ask I'm sure she would have told me about her. Maybe I should have spent less time admiring her Wesley voodoo doll and more time trying to find out more about who I didn't know in Buffy fandom.
But I don't think so. What I think, based on my observations over the thirteen years I've been involved in online fandom, is that everyone overestimates the size and importance of their fandom. It was true of the Melrose Place fans I hung out with in the AOL TV Gossip section, and of the Buffy fans at TWoP, and the Trading Spaces fans I used to hang out with over at the Trading Spaces Addicts' Place, and so on. Ultimately, what pretty much everyone means when they say something about fandom is, "the group of fans that I hang out with." There's nothing wrong with that, mind you; it's human nature. But it does mean that you need to take anything anyone says about "fandom" with a grain of salt. Including this.