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. Some of the most popular 3D chat experiences are IMVU and Second Life (though they extend far beyond just chat). Many such implementations generate profit by selling virtual goods to users at a high margin. Some online chat rooms also incorporate audio and video communications, so that users may actually see and hear each other. Games Games are also often played in chat rooms. These are typically implemented by an external process such as an IRC bot joining the room to conduct the game. Trivia question & answer games are most prevalent. A historic example is Hunt the Wumpus. Chatroom-based implementations of the party game Mafia also exist. A similar, but more complex style of text-based gaming are MUDs, in which players interact within a textual, interactive fiction–like environment. Rules of behavior Chat rooms, particularly those intended for children, usually have rules that they require users to follow. The rules are generally posted before entry, either on a web page or an MOTD-type banner in the case of IRC and other text-based chat systems. Rules usually do not allow users to use offensive/rude language, or to promote hate, violence, and other negative issues. Many also disallow impersonating another user. Chat rooms often do not allow advertising or "flooding", which is continually filling the screen with repetitive text. Typing with caps lock on is usually considered shouting (suggesting anger) and is discouraged. Offenders of these rules can be "kicked" (temporarily ejected from the room, but allowed back in) or banned completely, either on a temporary or permanent basis. 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. Yet, most commonly used chat rooms are not moderated and users may chat freely with the other occupants of the room. See also Email Internet Relay Chat List of chat websites Online chat References External links The Psychology of Cyberspace (2006)—E-book exploring the psychological aspects of online environments