Important announcements should be made on the game, be it through the announcements, a short OOC message sent to everyone, or a message put on the page, in the game is where the important announcements should be made.
Announcements are pointless. The game is long-term and announcements vanish after a short while.
The wiki is the proper place for the game "memory". Oh, and look:
http://wiki.battlemaster.org/wiki/Rules_and_Policies