Messages
The Messages screen can be used to post and read Guild Messages, you can set the permissions members have to access or post messages via the Titles tab of the Management screen.

Members with permissions to post can post new messages here, when posting a new message you have the option of entering a short Broadcast message, this is a small block of text that is sent as a guild announcement to everyone in your guild and can be used as a reminder to get a member to view the messages screen.