A BBS is an electronic bulletin board system, popular in the 1980s and early 1990s.
BBSes were the predominent form of online communication before the Internet became popular. One would dial into a BBS with a modem, and since most BBSes only had one phone line, they would read and exchange messages with other users who had accessed the system earlier. Most boards were free to use and were financially backed soley by the SysOp who run the board.
Inter-board communication was established through "Networks" which, in the BBSing scene consisted of arrangements where the machines that BBSes ran on would call each during the early morning hours and exchange new messages that had been posted on each board. Some networks were more advanced and used a "node/hub" system for forwarding messages and email between boards. One of the largest networks was FidoNet, a world-wide network that still exists today.
 See also
- textfiles.com - Archives of text files from BBSes