From Krakiipedia, the unofficial free GemStone IV encyclopedia.
GemStone IV is an immersive online roleplaying game set on Elanthia, on the major continent of Elanith. Each person who logs in assumes the appearance, background, and characteristics of a person, and then roleplays as that person in that shared world.
Each character will be from one of several races such as Human, one of several types of Elf, Dwarf, Giantman, Half-krolvin, one of two types of Gnome, one of two Simutronics-created races called the Aelotoi and Erithian, or a Halfling.
Each will also be from one of several professional training paths including your standard Warrior, Wizard, and Cleric, as well as the healing Empath, tricky Rogue, outdoorsy Ranger, devout and dedicated Paladin, knowledgeable Bard, mysterious Sorcerer, and spirited Monk.
After that, it's a matter of entering the world... and living in it.
GemStone IV is the latest incarnation of a game that dates back many years. See the GemStone history for more information.
http://www.play.net/gs4/ - Official GemStone IV website.