Science fiction fandom other groups including LGBT communities, libertarians, neo-pagans, and space activist groups like the L5 Society, among many others. Some groups exist almost entirely within fandom but are distinct and cohesive subcultures in their own rights, such as filkers, costumers, and convention runners (sometimes called "SMOFs"). Fandom encompasses subsets of fans that are principally interested in a single writer or subgenre, such as Tolkien fandom, and ("Trekkies"). Even short-lived television series may have dedicated followings, such as the fans of Joss Whedon's "Firefly" television series and movie "Serenity", known as Browncoats. Participation in science fiction fandom often overlaps with other similar
Science fiction on television being cancelled unreasonably is greatly increased by the attachment of fans to their favorite series, which is much stronger in science fiction fandom than it is in the general population. While mainstream shows are often more strictly episodic, where ending shows can allow viewers to imagine that characters live happily, or at least normally, ever after, science fiction series generate questions and loose ends that, when unresolved, cause dissatisfaction among devoted viewers. Creative settings also often call for broader story arcs than is often found in mainstream television, requiring science fiction series many episodes to resolve an ongoing major conflict.