What is a fanlisting?
Basically, a fanlisting is a type of fansite that is interactive and joinable. Most often, they stand alone, assuming that the visitor already has knowledge of the subject. However, sometimes a fanlisting can be a part of a larger fansite, such as a shrine.
According to The Anime Fanlistings Organization, "A fanlisting is a web clique that lists fans of a particular subject. Unlike most web cliques, a person does not need a web site in order to join. Fans from around the world submit their information to their approved fanlisting and they are then listed to show their love for the subject."
On the internet, the online community largely acknowledges TheFanlistings (TFL) and AnimeFanlistings (TAFL) as a major unifying force behind fanlistings. Their websites act as link directories to fanlistings, with rules and approval requirements. Fanlistings are not officially owned by the entertainment companies for the subjects they represent. These fanlistings are created by fans for fans. Fanlistings are not required to be a part of TFL/TAFL. However, to be approved by the respected TFL/TAFL community carries much weight in itself.
What is Episode 0?
Gundam Wing: Episode Zero is a manga prequel to the popular anime television series, Mobile Suit Gundam Wing (Shin Kidou Seki Gundam W). It covers 6 dramatic and beautifully drawn backstories of the main characters of the the tv series. There's a lot of good stuff in here: How Duo got his name and quirks, Trowa's time as a child mercenary, how Quatre met his crew of 40, Heero's mentor, Wufei's wife, and Relena original meeting with a perfect soldier. This manga is a must-read for anyone who considers themselves a GW fan.
It's about as canon as you can get, aside from the tv series storyline's manga adaption, as these back stories were orginally intended to be animated in the series. However, there planning conflicts, and they were not animated. The manga compliation also includes a chapter on the occurences immediately before the tv series (which did pieces of it animated in Endless Waltz), a special sequel to the end to the series/movie called "Preventer 5", and a note from the GW script writer.