Wikipedia
FanFiction.Net (often abbreviated as FF.net or FFN) is an automated fan fiction archive site. It was founded in 1998 by Los Angeles computer programmer Xing Li, who also runs the site. , FanFiction.Net is the largest and most popular fan fiction website in the world. It has nearly 2.2 million registered users and hosts stories in over 30 languages.
The site is split into nine main categories: Anime/ Manga, Books, Cartoons, Miscellaneous, Games, Comics, Movies, Plays/ Musicals, and TV Shows. The site also includes the Crossover category, added on March 27, 2009. Users who complete the free registration process can submit their fan fiction, maintain a user profile, review other stories, apply for a beta reader position, contact each other via private messages, and maintain a list of favorite stories and authors. There are centralized communities and forums. In lieu of signing up with a new account, FanFiction.Net allows users to use their Google, Facebook, or Twitter accounts.