The speculative fiction community is divided into unique sets of fandom. These fandoms are not just defined by what they like, but also how they speak and dress. Even the means of communication and where they congregate plays a role. So its not surprising that even a sub-genre like alternate history has a thriving, if small, community. What is unique about the alternate history fandom is that its size makes it so that it did not arise until a method of communication, namely the Internet, allowed for fans to congregate in significant numbers.
Now as far as I know, no one has done a serious study on this fandom, but I do know a little of the history of the group. In the spirit of what they like, I decided to present that history in a timeline format:
1970s: Sometime during this decade, Robert B. Schmunk found a copy of Robert Silverberg’s The Gate of Worlds at the Idaho Falls Public Library. He will later claim it inspired him to create a bibliography of alternate history fiction.
1987: KW Jeter coins the term “steampunk” to explain SF works set in alternate versions of the Victorian era, giving a name to the close cousin of alternate history (although they are often not on speaking terms) that would become a popular aesthetic, as well as literary, movement.
1990s: According to future Sidewise founder, Steven H Silver, alternate history experiences a small “boom” in the middle of this decade, that although never took off, did see fans begin to connect more over their shared passions.
1991: The Usenet Alternate History List was first posted by Schmunk on to rec.arts.sf-lovers, listing 250 works of alternate history after a request to help find published works in the genre. Most of the original list of 250 items were provided by Evelyn C. Leeper.
1995: The newsgroup soc.history.what-if was created for showcasing and discussing alternate histories. In that same year the first web version of the “Usenet Alternate History List” was created. Eventually the list would become web-only.
1996: The Sidewise Awards for Alternate History are presented at this year’s Worldcon. Meanwhile in New Zealand, Andrew Smith invents Brithenig, a constructed language based on the premise that Latin replaced Celtic as the primarily language of Britain, creating the romance language of Brithenig.
1997: The Usenet Alternate History List is converted into a website and renamed Uchronia: The Alternate History List. Elsewhere, Andrew Smith creates the Brithenig Project in an effort to explain how Brithenig came to be. It will eventually evolve into Ill Bethisad, one of the longest running collaborative timelines on the Internet.
1998: Island in the Sea of Time by SM Stirling is published. The initials of the title, ISOT, is eventually adopted as a slang term to mean a story where a person or place is transported to a different period of time.
2000: Ian Montgomerie creates Alternatehistory.com, a directory and discussion forum for alternate history on the web. Eventually, people from usenet groups would begin immigrating there. In this same year, Chris Nuttall created Changing the Times, an online magazine of alternate history that anyone could submit their work for inclusion.
2002: The constructed language of Wenedyk is created for Ill Bethisad, turning Polish into a romance language. Also this year, Alison Brooks passed away. Before her death she would later regret that “alien space bats” would evolve into a term used to describe a supernatural agency that created an alternate history.
2003: The first issue of Paradox: The Magazine of Historical and Speculative Fiction is published. Paradox featured short fiction stories with a historical setting and included many works of alternate history and related genres.
2004: Montgomerie updates AlternateHistory.com into a new format. The old directory is replaced solely by the discussion forum, which becomes the largest gathering of alternate history fans on the Internet.
2005: Wenedyk undergoes a major revision due to a better understanding of Latin and Slavic sound and grammar changes. Meanwhile, the Alternate History Wiki is created, a spiritual successor to Ill Bethisad, since many veteran contributors from there helped get it off the ground.
2006: Changing the Times is temporarily replaced by a German porn site. After that issue is sorted out, Nuttall hands over the administration to David Atwell.
2009: On May 12, the last issue of Paradox is released after the magazine failed to raise the necessary funding to remain in print.
2011: Matt Mitrovich created Alternate History Weekly Update as a news and reviews source on alternate history fiction. (Hey, shut up! I think its important!)
2013: Steampunk is predicted to be the next big thing according to an IBM supercomputer, much to the chagrin of alternate history purists.
2014: Uchronia reports that it lists over 3200 works of alternate history fiction.
I am sure I missed some important moments in this fandom’s history, so please feel free to share your thoughts in the comments. I am hoping to do a more serious study of the fandom in the near future, but this timeline is a good outline to begin with.