It seems there is some confusion on EVERYONES part on how to use the discussion board. There were some questions regarding collect postings and Marking As Read. When you collect posts there are a couple of ways to mark things read. Each message that you collect has a "Mark As Read" button in the bottom right corner of the message. You may also mark selected messages as read by checking the box at the right side of the message (near the heading) and then click the "Mark as Read" button at the top of the forum.
There also seems to be some confusion about students being able to see their discussion posts. There are two possible reasons why a student may not be able to see their discussion posts. First they need to understand the difference between Save and Submit. Save will basically allow them to set up a draft of their message; however it will not be public for you or their classmates unitl they click Submit which will make it public to the class. The other possible reason for not seeing their own messages is that they have not posted an original post but instead they have replied to one of their classmates. This replying to other classmates causes the message to be wrapped up in the thread and unless the thread is fully expanded the message they posted may not be immediatley visible to them. The threads can be expanded by clicking the plus sign that may be residing to the left of the message header.
One of the things that I would emphasize with your students is that when they are posting their original messages that they should use the +Thread button (add new thread).
Nancy