Talker
A talker in technical terms is a stripped down MUD that has only chat abilities. Talkers were seen as improvements on IRC in that they could be used to do more things. Using the MUD capabilities, they were able to be stylised to create an atmosphere of a virtual world.
Talkers were all but superseded by the advent of instant messengers such as ICQ, although talkers were never as popular as IRC, as they had not been about for as long.