Fandom is the diminutive of the expression in English fan kingdom, which means "realm of fans", in the literal translation into Portuguese.
a fandom is a group of people who are fans of a certain thing in common, such as a television series, a song, artist, movie, book, and so on.
This term was popularized through the internet, mainly through social networks, such as Twitter it's the Facebook, for example.
Like the fandons are common on the internet, its members tend to discuss virtually every subject related to what they are fans of.
In many cases, fandons organize physical meetings so that members of these communities can get to know each other in person.
Fandons are similar to popular ones fanclubs, which were successful in the 1990s. The big difference between them is in the use of online social networks as a tool to communicate, articulate and share their common tastes with people from all over the world.
Currently, fandons are essential for the growth and movement of the entertainment industry, as they are the main consumers of the media.
People who participate in fandons are the ones who most consume the media's products, in addition to being the ones who make the content reverberate on social networks and, consequently, become news for the traditional media (television and newspapers, for example).
See also: the meaning of shippar it's from fanfic.