created by Compu Serve executive Alexander "Sandy" Trevor in Columbus, Ohio.
Ancestors include network chat software such as UNIX "talk" used in the 1970s.
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.
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.