Fandom has been around for a lot longer than people realize, even in that way that goes beyond mild interest and towards those deeper fascinations that tend to spawn related activities. Charlotte and Emily Brontë wrote stories as children in the 1830s that we'd think of as fan fiction today. Charles Dickens was mobbed by American fans during his first trip here in 1842 — an experience he grew to dislike intensely, "Then by every post, letters on letters arrive, all about nothing, and all demanding an immediate answer." I'm also aware of at least one national convention held in New Jersey in the 1890s for dime novel fans.
This is not all exactly posting in subreddits and Bleeding Cool threads, but… it is steps towards that. (And, you know, a good thing it has just been baby steps. Who knows what might've become of poor Dickens if he'd had facebook in 1842?)
Another major leap forward towards modern fandom was instigated by Forrest J. Ackerman. When I saw pulp and vintage film historian Ed Hulse ( publisher of a well known fanzine on those subjects, Blood 'n Thunder) post that we've just passed the century mark on the date of Ackerman's birth, I asked him if he'd help us note the occasion:
Born on this day in 1916: The man who made respectable the serious study of horror and science-fiction films, Forrest J. Ackerman. A member of SF's "First Fandom" who was already contributing to pioneering fanzines in the early '30s, Forry as a literary agent later represented some of the genre's best writers.
His early chums and fellow fans included precocious writer Ray Bradbury and future special-effects guru Ray Harryhausen. At the behest of publisher Jim Warren, the avuncular "4SJ" (as he used to sign himself) in 1958 edited a one-shot magazine titled FAMOUS MONSTERS OF FILMLAND. It sold out and went into multiple printings, convincing Warren to make it a periodical and keep Forry on as editor.
A new generation was now seeing classic horror films on TV for the first time and embraced the new publication enthusiastically; among the future SF/horror filmmakers influenced by FMoF were young Steven Spielberg, John Landis, Joe Dante, and Peter Jackson, to name just a few. I visited Forry at his Los Angeles home — "the Ackermansion" — in the late 1980s and, like thousands of others before me, was amazed at the size and breadth of his collection. We reconnected many years later at a Pulpcon, where he was one of that year's Guests of Honor. Forry died in 2008 at the age of 92, and the one-of-a-kind collection he spent 80 years amassing was scattered to the winds in a series of auctions.