Talkomatic is an online chat system that enables real-time text communication among small groups. Each participant occupies a dedicated section of the screen, with messages appearing character-by-character as they are typed. Developed in 1973 by Doug Brown and David R. Woolley on the PLATO system at the University of Illinois, Talkomatic is recognized as one of the first multi-user chat systems, predating Internet Relay Chat (IRC) by 15 years and CompuServe's CB Simulator by seven years.
The system played a significant role in the development of online communities and influenced subsequent collaborative software, including Lotus Notes. After the original PLATO implementation was discontinued in the mid-1980s, Brown and Woolley released a web-based version in 2014. Following a temporary shutdown in 2024, the system was revived as an open-source project.