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Second Life and Wonderland are not the only virtual world environments by any means. Below is a partial list of interactive environments with at least 1 million registered users.
* Sun's DarkStar and Wonderland platform and client - open source projects
* Croquet Project Consortium - open source
* There.com
* Twinitiy
* Habbo Hotel - the world's largest virtual hangout
* Utherverse
* Gaia
* Stardoll - design a celebrity avatar
* Meez - create and export your own 3D avatar
* vMTV - MTV's Virtual World chatroom
* Active Worlds
* Entropia Universe
* Kaneva - a Virtual World for gamers
* Hipihi - Chinese Virtual World
* Cybertown - Civilization for the Virtual Age
* IMVU - 3D chat
* moove online
* 3B - your personalized 3D space in the 3D browser
* Gogofrog
* Club Marian
To view research on current Virtual Worlds including demographic breakdowns, case studies, and diagrams please visit KZero
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