Why always StarWars?????
Fan fiction (alternatively referred to as fan-fiction, fanfiction, fanfic, FF, or simply fic) is a broadly-defined fan labor term for stories about characters or settings written by fans of the original work, rather than by the original creator. Works of fan fiction are rarely commissioned or authorized by the original work's owner, creator, or publisher; also, they are almost never professionally published. Because of this, many stories often contain a disclaimer stating that the creator of the work owns none of the characters. Fan fiction, therefore, is defined by being both related to its subject's canonical fictional universe and simultaneously existing outside the canon of that universe. Most fan fiction writers assume that their work is read primarily by other fans, and therefore tend to presume that their readers have knowledge of the canon universe (created by a professional writer) in which their works are based.
You can read more about Henry Jenkins and his book Convergence Culture here.