The term chat room, or chatroom, is primarily used by mass media to describe any form of synchronous conferencing, occasionally even asynchronous conferencing. The term can thus mean any technology ranging from real-time online chat over instant messaging and online forums to fully immersive graphical social environments.

Text-based chat

Online chat is a way of communicating by sending text messages to people in the same chat-room in real-time. Some chat rooms such as Yahoo! use both text and voice simultaneously. The oldest form of true chat rooms are the text-based variety. Talkomatic, developed on the PLATO System around 1974, has a strong claim to have been the prototype of the text-only chat room. A notable 1980's text-based chat system was Freelancing' Round table. The most popular of this kind is Internet Relay Chat (IRC). The popularity of these kinds of chat rooms has waned over the years, and IRC's popularity has rapidly given way to instant messaging. Also a notable number of people were introduced to chat rooms from AOL and web chat sites.

There are also graphical user interface (GUI) text-based chat rooms which allow users to select an identifying icon and modify the look of their chat environment.

Graphical multi-user environments

Visual chat rooms add graphics to the chat experience, in either 2D or 3D (employing virtual reality technology). These are characterized by using a graphic representation of the user (avatar) that can be moved about a graphic background or in a graphic environment. These virtual worlds are capable of incorporating 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 also allow users to create or build their own spaces.

Some visual chat rooms also incorporate audio and video communications, so that users may actually see and hear each other. However, some find these types of environments cumbersome to use and actually an impediment to chatting.

Chat room activities

The primary use of a chat room is to share information via text with a group of other users. New technology has enabled the use of file sharing and webcams to be included in some programs and almost all Internet chat or messaging services allow users to display or send to each other photos of themselves. With a prolific rise in the activity of 'Sexting', where people send digitised nude or otherwise sexually explicit photos of themselves electronically to be viewed by others, it is becoming increasingly common for chat room users to exchange nude or sexual photos.

Some people who visit chat rooms use them as a place to experience online sex, also known as cybersex or computer love. While not physically able to see their partner, cyber-ers get stimulation by reading x-rated quotes. While many in the media focus on this aspect of chat rooms as it certainly boosts their ratings, it is by no means the only thing chat rooms are used for. While many people engage in "cybersex" for many reasons, it is also true that sexual predators use cybersex conversations as a means of identifying potential victims.