Online chat may refer to any kind of communication over the Internet, that offers a real-time direct transmission of text-based messages from sender to receiver, hence the delay for visual access to the sent message shall not hamper the flow of communications in any of the directions. Online chat may address point-to-point communications as well as multicast communications from one sender to many receivers and voice and video chat, or may be a feature of a web conferencing service.
Online chat in a less stringent definition may be primarily any direct text-based or video-based (webcams), one-on-one chat or one-to-many group chat (formally also known as synchronous conferencing), using tools such as instant messengers, Internet Relay Chat (IRC), talkers and possibly MUDs. The expression online chat comes from the word chat which means "informal conversation". Online chat includes web-based applications that allow communication –often directly addressed, but anonymous between users in a multi-user environment. Web conferencing is a more specific online service, that is often sold as a service, hosted on a web server controlled by the vendor.
The first online chat system was called Talkomatic, created by Doug Brown and David R. Woolley in 1974 on the PLATO System at the University of Illinois. It offered several channels, each of which could accommodate up to five people, with messages appearing on all users' screens character-by-character as they were typed. Talkomatic was very popular among PLATO users into the mid-1980s.
The first dedicated online chat service that was widely available to the public was the CompuServe CB Simulator in 1980, created by CompuServe executive Alexander "Sandy" Trevor in Columbus, Ohio. Ancestors include network chat software such as UNIX "talk" used in the 1970s.
The term chatiquette (chat etiquette) is a variation of netiquette (Internet etiquette) and describes basic rules of online communication. To avoid misunderstandings and to simplify the communication between users in a chat these conventions or guidelines have been created. Chatiquette varies from community to community, generally describing basic courtesy; it introduces new user into the community and the associated network culture. As an example, it is considered rude to write only in upper case, because it appears as if the user is shouting.
Cultural impact 
Social criticism 
Writing is changing as it takes on some of the functions and features of speech. Internet chat rooms and rapid real-time teleconferencing allow users to interact with whoever happens to coexist in cyberspace. These virtual interactions involve us in 'talking' more freely and more widely than ever before. With chatrooms replacing many face-to-face conversations it is necessary to be able to have quick conversation as if the person were present, so many people learn to type as quickly as they would normally speak. Critics[who?] are wary that this casual form of speech is being used so much that it will slowly take over common grammar; however, such a change has yet to be seen.
With the increasing population of online chatrooms there has been a massive growth of new words created or slang words, many of them documented on the website Urban Dictionary. Sven Birkerts wrote:
"as new electronic modes of communication provoke similar anxieties amongst critics who express concern that young people are at risk, endangered by a rising tide of information over which the traditional controls of print media and the guardians of knowledge have no control on it".
This person is arguing that the youth of the world may have too much freedom with what they can do or say with the almost endless possibilities that the Internet gives them, and without proper controlling it could very easily get out of hand and change the norm of literacy of the world. In Guy Merchant's journal article Teenagers in Cyberspace: An Investigation of Language Use and Language Change in Internet Chatrooms; Merchant says
"that teenagers and young people are in the leading the movement of change as they take advantage of the possibilities of digital technology, drastically changing the face of literacy in a variety of media through their uses of mobile phone text messages, e-mails, web-pages and on-line chatrooms. This new literacy develops skills that may well be important to the labor market but are currently viewed with suspicion in the media and by educationalists.
Merchant also says "Younger people tend to be more adaptable than other sectors of society and, in general, quicker to adapt to new technology. To some extent they are the innovators, the forces of change in the new communication landscape." In this article he is saying that young people are merely adapting to what they were given.
Software and protocols 
The following are common chat programs and protocols:
Chat programs supporting multiple protocols:
Web sites with browser-based chat services (also see web chat):
See also 
- Chat room
- Collaborative software
- Instant messaging
- List of virtual communities with more than 100 million active users
- Live support software
- Online dating service
- Real-time text
- Stranger chat
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