Realtime chats are the most common realtime applications. If there is a realtime service, they offer realtime chat in some capacity or form.
WebSockets are the most preferred mechanism to create realtime chat because they are bi-directional, meaning messages can be sent back and forth between a client and a server.
Live Chat vs. Realtime Chat
Sometimes people confused realtime chat and live chat. Live chat is a popular term for online chat applications that provide assistance to a user. Live chat is more of a support mechanism on most sites. Realtime chat involves the instantaneous delivery of messages from a sender to a receiver.
Real World Applications
Realtime chat programs:
- Google Talk
- Windows Live Messenger
- Google+ hangouts
If you want to see a realtime chat in live action, check out Socket.IO’s chat demo here.
Citing Techopedia: “The first real-time chat system was known as Talkomatic, developed by David R. Woolley and Doug Brown in 1973. It provided quite a few channels, each of which was able to support as many as five people, with messages from all users showing up on the screens character-by-character as they were typed. CompuServe CB Simulator, launched in 1980, was the first dedicated real-time chat service made available to the public.”