Gaia Online

Gaia Online (previously known as Go-Gaia, informally called Gaia) is a roleplaying site founded on February 18, 2003 by Derek Liu (Gaia username Lanzer), Josh Gainsbrugh (username L0cke), Long Vo (username VO) and a team of their friends. The site currently revolves around its forum, avatars, and in-game currency, but is expanding to include features such as games and user-versus-user dueling.

Gaia's forum, the largest English-language forum-based community on the internet, has over 250 million posts (plus over 191 million in storage), 2 million registered users, and usually has 20,000 or more people online at any given time during the day.

Users earn "gold" by posting, lurking, answering polls, and through random events. Once a user has earned gold, they can use it to buy items to dress up their avatar.

Gaia and furry
There are furry avatar bases available (cat, wolf, bear, fox) as well as many furry-themed items for human avatar bases, such as various tails, ears, and paws for many species and potions that turn your human avatar into a centaur.

There are many organized furry communities on Gaia. . The oldest furry guild on Gaia Online is the AFG (Absolute Furry the Guild -formerly the Adult Furries Guild) which has over three thousand members. There are also places like The High Tail Cafe, which is a mostly a RP Community Guild open to all ages. The AFG was founded over ten years ago by J.Kougar and friends, but is currently moderated by _The_Black_Magic_Bunny_.