(BBS, bboard /bee'bord/; after a physical piece of board on which people can pin messages written on paper for general consumption - a "physical bboard"). A computer and associated software which typically provides an electronic message database where people can log in and leave messages. Messages are typically split into topic groups similar to the newsgroups on Usenet (which is like a distributed BBS). Any user may submit or read any message in these public areas.

Apart from public message areas, a BBS may provide archives of files, personal electronic mail and any other services or activities of interest to the bulletin board's system operator (the "sysop"). Thousands of local BBSes are in operation throughout the world, typically run by amateurs for fun out of their homes on MS-DOS boxes with a single modem line each. Although BBSes have traditionally been the domain of hobbyists, an increasing number of BBSes are connected directly to the Internet, and many BBSes are currently operated by government, educational, and research institutions. Fans of Usenet and Internet or the big commercial time-sharing bboards such as CompuServe, CIX and GEnie tend to consider local BBSes the low-rent district of the hacker culture, but they serve a valuable function by knitting together lots of hackers and users in the personal-micro world who would otherwise be unable to exchange code at all.

Use of this term for a Usenet newsgroup generally marks one either as a newbie fresh in from the BBS world or as a real old-timer predating Usenet.