Some of the most popular 3D chat experiences are IMVU and Second Life (though they extend far beyond just chat).
These are characterized by using a graphic representation of the user, an avatar (virtualing elements such as games (in particular massively multiplayer online games) and educational material most often developed by individual site owners, who in general are simply more advanced users of the systems.
The most popular environments, such as The Palace, also allow users to create or build their own spaces.
Years ago when AOL was still popular they had hundreds of them, and I remember when Yahoo began their chat rooms.
Have talk boards like this and similar forums done away with chat rooms?
The term chat room, or chatroom, is primarily used to describe any form of synchronous conferencing, occasionally even asynchronous conferencing.
The term can thus mean any technology ranging from real-time online chat and online interaction with strangers (e.g., online forums) to fully immersive graphical social environments.
The first created by Compu Serve executive Alexander "Sandy" Trevor in Columbus, Ohio.
Visual chat rooms add graphics to the chat experience, in either 2D or 3D (employing virtual reality technology).
Sometimes chat room venues are moderated either by limiting who is allowed to speak (not common), by having comments be approved by moderators (often presented as asking questions of a guest or celebrity), or by having moderation volunteers patrol the venue watching for disruptive or otherwise undesirable behavior.