How do I find unread messages?

For those not logged in, the Recent posts link showing in the Navigation menu in the left-column will show a list of all published content open to public view arranged - by default - from the most recent to the oldest. When someone is logged in, the system will remember when their last login occurred and change the display of that list to indicate new or updated content. (The person's username will show at the top of the Navigation menu while logged in.) Filters also exist in this area, as well as others, to help someone narrow the list display in various ways, such as limiting it to those in the forum or calendar.