From Wikipedia
Island of Kesmai was an early commercial online game in the MUD genre, innovative in its use of roguelike pseudo-graphics. It is considered a major forerunner of modern MMORPGs.
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After logging into Compuserve and selecting to play Island of Kesmai, the user was allowed to create a character. After creating a character, the next step was to enter the chat room. From the chat room, the user could enter the virtual world.
The game interface was two dimensional and scrolled unless you downloaded and installed a GUI. The interface has often been called roguelike in that it borrowed features of game-play from a game called Rogue. The game used a Dungeons and Dragons-like turn-based play. Players moved in tiles on a grid utilizing short commands or key presses. Items could be found on the floor of the dungeon as symbols — as could mobs to fight.
One of the notable game play systems was the ability to perform quests for various rewards.