Fan fiction, also called fanfiction, is derivative fiction written using another author's characters and universe. Fanfiction authors write stories about their favorite characters from books, movies, or comics. This cannot be sold, because the original characters and universe are copyright to the original author.

Fanfiction can be shared, however, so long as no money is involved. For instance, if you are a fan of Stargate SG-1, then you might write stories about the characters that you know so well from watching 8+ seasons of them. Your story would be "fan fiction" because it isn't officially part of the show or the official histories of the characters, and you could post it online or share it in a newsletter between friends.

Most fanfiction authors are youngsters just starting out, so most fanfiction is poorly written. However, there are quite a few accomplished fanfiction writers who have mastered the art of writing a good story, and even the new authors are getting practice at the art. The majority of fanfiction is written by women (some studies say as much as 80 percent), and is romantic in nature.

Here are some terms you will see associated with fanfiction

• Canon is the original body of fiction written by the original author
• Fandom refers to a group of people who enjoy a specific work of fiction - they often get together online or in person to talk about their favorite books, movies, comics, etc.
• Slash stories are erotic tales with same-sex pairings. This term started in the 1960's with fanfiction about Star Trek - so many people wrote and shared stories about Kirk and Spock "getting it on" that they began abbreviating these stories as "Kirk/Spock" which is read "Kirk-Slash-Spock" - this soon became a common term to denote any same-sex pairing, and from then it was shortened even further to just "slash" - the opposite of slash is het. Sometimes, when the same- sex pairing is between two females, it can be called 'femmeslash' or 'femslash'.
• Gen stories are the ones without graphic sex - this is an abbreviation of the term "general" fiction. Often a story will be classified as "gen" if the fanfiction author does not have a specific category (such as mystery, romance, or adventure)
• Dojin/Dojinshi is the Japanese version of fanfiction - this also originated in the 1960's and is usually about anime or manga characters
• Lemon stories are the Japanese graphic sex stories - this term comes from the "Cream Lemon OVA" anime series
• Yaoi/Shonen-ai and Yuri/Shojo-ai are the Japanese versions of slash. Yaoi is gay male and Yuri is lesbian - both are more sexually explicit than shonen-ai or shojo-ai stories
• PWP stories - it either stands for "Porn Without Plot" or "Plot, What Plot?" - are stories that make no effort to make sense, and are just an excuse to write a sex scene
• Ship or Shipper - this term is short for "relationship" and refers to the favorite romantic couple of a fanfiction author - also called pairing. Sometimes the fanfiction authors "smoosh" the names of the two characters together (Severus Snape/Harry Potter makes Snarry)
• One True Pairing or OTC refers to the fanfiction's opinion about which characters are "perfect" for one another
• Alternate Universe or AU stories involve changing the original fiction in a dramatic way, such as an alternate timeline instead of the way things evolved in the original fiction, or changing the characters' personalities from the way the original author wrote them
• Crossover stories take characters from different works of fiction and put them into the same story (for example, Buffy travels to Hogwarts, or Edward and Bella visit Middle Earth)
• Hurt/Comfort or H/C stories involve having one character injured or ill, and the other character takes care of them - a favorite story of young girls
• Songfic stories are also favorite stories for young girls - these involve copying the lyrics to their favorite song and writing a story around the characters either listening to the song or performing it
• Mary Sue characters - this term also began with Star Trek, with a character named Mary Sue who came aboard the Enterprise and proceeded to have romantic encounters with every member of the officers and crew, knew how to do everything aboard ship, and was so perfect that everyone who read the stories despised her. Mary Sue (the male version is Marty Stu or Gary Stu) characters are usually meant to represent the fanfiction author, or at least the way the author would like to be. They have unrealistic talents and skills, are beautiful or handsome beyond belief (often with oddly-colored hair and eyes), and usually cause most of the original characters to fall in love with them. Mary Sue characters are almost always written by young girls, and are often half human and half mystical creature (half-mermaid, half-centaur, half-dragon, etc). These stories also contain long descriptions of clothing and other personal adornment, and may be songfics

Many authors do not mind fanfiction - some even consider it flattering! - but many also resent such derivative fiction. Anne Rice is one author who is violently against fanfiction; JK Rowling is one author who finds fanfiction flattering. Before posting your fanfiction on the internet, you should check out the original author and be sure that they are not going to resent your work.