Being an extremely cursory timeline of fan fiction and fandom based on my dipping of my toes into the waters of Studies in Fan Culture.
(Inspired in part by Cracked.com's recent article on pop culture and fanfic, which, be warned, is very funny but also very not at all PG. I like my blog PG and will warn in advance if it is not. Article contains the whole gamut of potentially disturbing subjects.)
1136-1200 AD. The King Arthur stories. Of course, you say, these are myths. They don't count. But the original King Arthur and the Round Table story was expanded upon by other authors extensively, most notably by the addition of Lancelot in 1136 by Chretien de Troyes. Some scholarship has been done on Lancelot being inspired by similar Welsh heroes, but he was first "imported" into the King Arthur mythos in de Troyes' work. The site linked to above notes that "The poet seemed to assume that people have already read Chretien's Conte du Graal", with 'Graal' being the first text in which Lancelot appears. Maybe it's not fan fiction per se, but it's certainly expansion. It is fiction with the intent of a previous fictional world existing behind it.
1719. Unauthorized sequel(s) to Robinson Crusoe.
1728, The Beggar's Opera. I note that the wikipedia article lacks sources, but can cite the source of Some Overenthusiastic British Professors I Studied With as well. "The Beggar's Opera" was the 1700s equivalent of Glee. It used popular songs, and parodied the Italian operas popular at the time. People liked to buy stuff with the characters' faces on it. Strange but true.
1787. The Sorrows of Young Werther is published. This novel is the poster child for German Romanticism. It also spawned a fandom of people who dressed like the main character, and committed suicide in imitation of him. Yes. Werther was adapted into an opera in 1887. I'm not sure if there were amateur derivative stories produced based on it, but that's what my next huge paper is for.
1887. Sherlock Holmes fan fiction and fan groups. The Fan History Wiki has a nice timeline of derivative works.
1967. Star Trek fanzines created fan fiction as we know it today. These were mailed or hand-distributed anthologies of fan works. Slash and/or adult content were common, possibly leading to that trend (or that stereotype) being so predominant today. These magazines also created some of the terms and punctuations ( the use of "/" in pairings, for example) that we use today. Zines are considered a collector's item today, and to see them in print is rare or impossible, because the same needs are met by the much easier medium of the internet.
Some people are bringing zines back because they like the format, or for the retro feel. My own work should be appearing in a printed Zoids fanzine any time now. However, the big difference is that these zines feature international authors through connections only made possible by the use of the internet.
1998. Fanfiction.net is founded. Things change. Fans now have an organized, easy-to-use sharing system. It's not perfect, but that's another post.
Told you it was cursory, but there's the timeline. Hopefully you've learned that fan fiction and fandom are in no way new phenomena, and that aspects of them have been studied in an academic setting before.
Next post coming soon.