The Bulletin Board is a public forum for communication between all Avalonians on global issues. Select boards have restricted access, requiring you meet certain criteria in order to view.
This is one of the commands most likely available to you while you are playing Avalon. Here is what information we have on the "BB" command:
The Avalon bulletin board is a method for all Avalonians to maintain contact with each other. It should be used for notices and messages relating to world-wide issues and as a convenient method for Cities, Guilds and Orders to speak to the assembled masses. Type BB to enter the bulletin board or BBSTATUS within Avalon to discover whether there are any new messages. You may also use READBB to apprise yourself of the contents whilst still in the land. HELP once inside the bulletin board will give you information.
In most circumstances you will be able to enter the bulletin board (after the twelve second delay) wheresoever you are in Avalon and in whatever form you are clothed. Some exceptions are: when you are in the ethereal winds, while you hold more than five of a material commodity in your inventory (unless it belongs to you).
There are a great number of selective-entry bulletin board sections in addition to those mentioned above, including separate boards for members of government, guildmasters, elders over a century (in Avalon years), comments about Avalon, treaties between cities and guilds, etc. You will know you have access to a selective-entry section when it appears in your BBSTATUS list.