Background

In the 70s, there was MUD. MUD stands for Multi-User Dungeon and it is a text-based virtual world that players connect to through Telnet. Players connect to the MUD and interact with others or the world by inputting commands. They get feedback and information from text description. Later in the 80s, some graphical virtual worlds based on MUD were released. They were actually MUD which changed the present method from text to graphic and from command input to GUI input.

Later, Ultima Online (http://www.uoherald.com/) and EverQuest (http://www.everquest.com/) brought multiplayer virtual worlds to a new level. World of Warcraft (http://www.worldofwarcraft.com) and Second Life (http://secondlife.com/) followed EverQuest and they all made the trend of online games and virtual worlds.

In recent years, Flash virtual world is becoming more popular. Many new virtual world communities released Flash-based instead of traditional installer-based. In the beginning, Flash virtual world is not mature due to the performance issue of Actionscript 1 and old Flash player. After the introduction of ActionScript 2 and ActionScript 3, the programming language has been enhanced and the performance of Flash player boosts to support better network connections and better graphics. This makes the spring of Flash virtual world.