Shipping is a fandom practice that involves imagining relationships between two fictional characters from a show, movie, or book series. This ranges from canon relationships (ones that appear in the work) to alternate universe scenarios that would be highly unlikely to ever occur in the normal storyline. Shipping can be seen in fanfiction and fan art of the imagined couplings.
One of the first fan bases focused on the fictional characters' relationships were centered on Jane Austen’s novels including Pride and Prejudice and Sense and Sensibility. In 1913, a book entitled Old Friends, New Fancies was published, depicting characters from three of Austen’s novels interacting and building new romantic relationships. The Pride and Prejudice character Mr. Darcy had also been a popular subject of fan fiction and art, dating back to the early 1900s to recently being the subject of a Hark! A Vagrant comic that would become the exploitable Ooh Mister X.
The phrase "shipping" derives its origin from "relationshipper." However, both terms were used interchangeably in conversations across newsgroups. One of the earliest archived examples of the word in use dates back to May 28, 1996 in posts on a small X-Files newsgroup. The term was then again used in 2006 by another X-Files fan on the same newsgroup.In this thread, a user complains about “relationshippers,” stating that if the show’s protagonists Mulder and Scully were to date, the dynamic of the show would be ruined.
As bloggerss began to migrate to LiveJournal, shippers did as well. In August 2004, The Shipper's Manifesto launched as a springboard for people to share essays about their favorite ships. As of January 2013, the community hosts 1000 essays on relationships from a variety of fandoms. Additionally, there are hundreds of communities for fans of specific ships that share the interest "shipping."
Shipping communities on Tumblr have evolved into their own fandom-specific confession blogs, in which users submit anonymous secrets about the relationships they favor, often via a photo of the couple with text on it. One of the earliest ones was for Glee, which began in April 2010. Other notable examples include Harry Potter, Naruto, and a general, all fandom confession blog. The shipping community on Tumblr is quite active under the tags "#shipping", "#ship", and "#shippers gonna ship". Often, shippers will not limit themselves to one fandom, participating in shipping from a variety of different subcultures they are interested in.
OTP, short for One True Pairing, is the term used to refer to a person's favorite couples or the ones to whom they invest the most of their emotions. Fans can have more than one OTP, although they do not usually involve the same character more than once. The acronym was first defined on Urban Dictionary in September 2003, however was in use on LiveJournal fan communities as early as October 2002, as documented in a post about the boy band NSYNC.
In some ways, this is my OTP, if by "true" we're talking about what I really think is canonically plausible. Even if it's not a sexual thing (though I think it is, or has been), they vacation together, they're off on their bus together with Joey & Lance's Animal Planet, Lance is the one Joey wanted as godfather to his child, they double date with Tom Hanks and Rita Wilson.
Slash is the term used for homosexual pairings, frequently seen with characters who have not shown signs of being gay in the original canon. Although the term originally referred to imagined romantic relationships between two male characters, the term now refers to romantic pairings of any kind between same gendered characters
The first widely distributed slash fanfiction was published in September 1974 in the third issue of the Star Trek fan zine Grup. Entitled “A Fragment Out Of Time,” the story fantasized a sexual relationship between Kirk and Spock whose names were never mentioned in the text. As more stories featuring homosexual pairings were published, authors would use a slash between the two names (“Kirk/Spock”) in their descriptions instead of an ampersand ("Kirk & Spock"). Since the ampersand traditionally denoted platonic pairings in fan fiction, use of the slash became a warning to readers that the characters would be paired romantically. One of the earliest printed examples of the word "slash" being used to describe this type of pairing dates back to a Letter of Comment published in a nonfiction Starsky & Hutch fanzine from February 1981.
Some of the earliest online slash stories were posted to the X-Files newsgroup beginning in May 1995. Between 1999 and 2006, several in-depth essays about why people write and enjoy slash were shared on the Fanfic Symposium.
Crack Pairings refer to a type of coupling that is considered bizarre or absurd due to various reasons, such as lack of relevancy in the canon or discrepancy in age or species of the characters that are involved. The name comes from the assumption that whoever created such pairing was on crack at the time.
In 2003, a LiveJournal community called VeryWrongSlash was created to share stories with untraditional pairings, but they were not explicitly called "crack." The first story published featured Goofus and Gallant, characters from a comic that has appeared in the children's magazine Highlights since 1948.
Crack pairings had dedicated LiveJournal communities as early as March 2005. It was first defined on Urban Dictionary in June 2006. In September 2007, the crack LJ community brain_asplode created a generator for these pairings on the fanfiction writer's reference tool site Seventh Sanctum. There is also a TVTropes page to collect these works.
Shipping Charts refer to tables and charts created by fans of certain series showing possible romantic relationships. Also known as Love Charts, they commonly use a system of colors or symbols to show the types of relationships these characters are involved in, occasionally accompanied with detailed explanation to clarify possible flaws. These diagrams sometimes show the relationships accepted in the canon, but fans mainly use them for their imagined relationship purposes. Many series also have official diagrams of canon relationships to help fans keep track of what is going on, including one published on the back of the third issue of the Scott Pilgrim series.
Shipping Charts can be seen as an expansion on Love Triangles, romantic relationships involving three people. Whereas only three people can be relatively easy to oversee, adding one or multiple characters to the mix can cause a lot of confusion for fans.
Shipping Wars are flame wars that take place between supporters of contradicting OTPs, two relationships featuring the same character paired with different love interests. This can either occur textually through comments or through fan art, representing these OTPs with actual ships. Due to the strong devotion of many shippers to their favorite pairings, long and angry arguments are known to occur between the shippers, often delving into insulting and personally threatening the opposing sides.
 Austen Blog – REVIEW: Old Friends and New Fancies by Sybil G. Brinton
 ontd_startrek LJ Community – The Female Gaze and Male Gays: Exploring Slash Fanfiction in Online Communities and Feminist Contexts