Gaia is mostly anime-themed. There are forums where you can chat with others. There are arenas, you can show off your avatar, your house, and you can show off artwork {pictures you drew, photographs} you can also put up stories you wrote for others to rate and comment.
When you start you create an avatar. You pick the gender, hair style and color, eye style and color. As you get oriented with Gaia you earn gold, the currency, and you can buy items for your avatar or your house or car.
Gaia has its own storyline, mostly on holidays. As the story goes on Gaians, the users, participate in events that help shape the world of Gaia. If you want to read the storyline so far here it is http://www.gaiaonline.com/newsroom/?type=manga
There are several game, pinball, puzzles, blackjack, etc... But there is one a new game, it is called the zOmg! You get to go into the world of Gaia and fight the animated with rings. {Its seriously a LOT more interesting than it sounds.} With of course the totally cliched, if you dont succed the world gets destroyed.
But its fun.You can also go to the cinemas and watch some movies, or walk through the towns and visit friends' houses.
For more info click this link http://www.gaiaonline.com/info/whatisgaia/?_gaia_t_=906
Also if you join, there is a website that is a tool for Gaia, here is its link http://www.tektek.org/index.php
On Tektek you can create Dream Avi's, find cool profile themes and there are several other tools for Gaia.
