You and oher people use an internet chat program to connect to a chat server on the Internet.The chat server acts as host,typically offering hundreds of chat rooms(on hundreds of topics)where people can gather to chat.As you type and send messages, your messages appear on the screen of everyone in the chat room.As the other people in the room type and send messages,they appear on your screen.

Physical chat

• TEXT CHAT--it is the ability to communicate on the internet via typing text back and forth
• VOICE CHAT--it is the ability to communicate on the Internet by voice....almost same as in telephone calls..
• AUDIO-VIDEO CHAT--it is the ability to communicate on the Internet via voice,whiteboards(software which has tools of drawing etc so that the people share the same document and make an agreement)and showing real time online video.
• MULTIMEDIA CHAT--it show a 3D world where each item represents a particular character.

TYPES OF CHAT

• Internet relay chat(IRC)
  Internet chat started with IRC.Using a program, such as VisualIRC or PIRCH, you can connect to an IRC server and chat with users in other rooms.This is relaltively complicated way to chat on the internet, but it does draw thousands of chatters.
• Web form chat
  In an attempt to bring the simplicity of the web to the world of chat, developers came up with web form chat.To send a message, you fill out a form and click a button.The web chat site automatically sends an updated web page to everyone in the room, showing everybody's recend messages.This type of chat is cumbersome and not very popular.
• Web client chat
  This type of chat is currently the best way to chat on the web.With a web browser and the right plug-in or activeX control, you can chat right inside the browser window.Eg iChat.
• Avatar and Comic Chat:
  Avatar and Comic chat allow you to play the role of a particular character in a chat room.You can then move the character around in the room, gesture to other chatters, and even bump into people.To use avatar or comic chat, youneed a special chat program, such as Microsoft V-Chat or worlds away.