From PBS:
Before mass media, people actively engaged with culture through
storytelling and expanding well-known tales. Modern fan culture
connects to this historical tradition, and has become a force that
challenges social norms and accepted behavior. Whether the issue is
gender, sexuality, subversiveness, or even intellectual property law,
fans participate in communities that allow them to think outside of
what is possible in more mainstream scenarios. "Fannish" behavior has
become its own grassroots way of altering our society and culture, and
a means of actively experiencing one's own culture. In a sense, fans
have changed from the faceless adoring masses, to people who are proud
of their identity and are stretching the boundaries of what is
considered "normal".