Fandoms surrounding the favorite books of teenagers have been a prominent part of culture since the Harry Potter books. Now, most well-loved series have some kind of derivative fandom surrounding them, but the Harry Potter fandom is by far the most expansive example of this. Years ago, Harry Potter fans pushed past the creation of art, parody musicals, and actual sports, and they went a step further by channeling their love for the books into the creation of an activist group.