CBBS was the bulletin board system launched in Chicago in 1978.
CBBS stood for Computerized Bulletin Board System and was created by Ward Christensen and Randy Suess. The idea grew out of the Great Blizzard of 1978, when the two Chicago computer hobbyists wanted a way to exchange messages and files despite being unable to meet in person.
The system used a home-built computer and modem. Users dialed directly into it over telephone lines, because the Internet was not yet a normal public-access network. For most of its early life, CBBS supported only one modem connection, so users had to take turns accessing the board.
CBBS helped establish features that became standard in later bulletin board systems, including message bases, file exchange, and user interaction. FidoNet was a later network linking independent BBSs, while The WELL was a separate online community that began in 1985.