Online 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. Freelancin'_Roundtable was a modem-based text chat system in the 1980s. The most popular of this kind is Internet Relay Chat (IRC). However, there are also talkers and havens. 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.
Reference : http://www.uthaisak.net/wikipedia.htm