What is a fanlisting?

"A fanlisting is simply an online list of fans of a subject, such as a TV show, actor, or musician, that is created by an individual and open for fans from around the world to join. There are no costs, and the only requirements to join a fanlisting are your name and country."
... As quoted from TheFanlistings.org. This particular fanlisting is dedicated to uniting fans of the character Azumane Asahi from the manga and anime series Haikyuu!!. It is listed at AnimeFanlistings.com.