The Announcements tool is used to inform site participants about current items of interest. Announcements can have multiple attachments, such as documents or URLs.
Sorting: You can sort announcements by subject, sender, access, or date.
Posting: Announcements are posted to a course or project site. Site owners and instructors can choose to have an announcement automatically sent via email to all site participants by using the "low" or "high" notification setting. For more information on managing email, see Tools for managing site email.
Showto make it visible,
Hideto hide it, or
Specify Datesto set a beginning date and ending date for the announcement's visibility.