So, modern fanfic…

All right, fine. Contemporary fanfiction—i.e., fanfiction emerging from a collective, community fandom—can be traced to one of two main sources. The first is Star Trek. The second is Sherlock Holmes. (Hilariously, not much has changed. The Star Trek and Sherlock fandoms are still around!) Star Trek fandom is generally credited with a lot of archival work and with producing fanzines that regularly made it into the hands of Gene Roddenberry himself. He even said in a letter to the Spokanalia fanzine publishers that the zine was “required reading” in the office.
In fact, Star Trek: The New Voyages is a collection of fanfiction that was traditionally published by Bantam Books, with a forward by Roddenberry that reads:
It is now a source of great joy for me to see their view of Star Trek, their new Star Trek stories, reaching professional publication here. I want to thank these writers, congratulate them on their efforts, and wish them good fortune on these and further of their voyages into other times and dimensions