On another document in your mailbox you find specific information about the course structure, assignments, tests, the grading system, and how your attendance will be taken. As you look around again you find that other students and the instructor each have a mailbox. A notice above the mailboxes says that only the owner of the mailbox will receive messages put into that box. When you look back at the marker board you learn that messages written on the marker board or tacked to the bulletin board can be read by anyone in the class. Another note tells you that the classroom is always open and you are welcome to drop by any time you like.
Security is never a problem because only registered students are able to enter the building.
After a couple of days you begin regular visits to the classroom. Each time you visit you find additional messages from your instructor with instructions for the next section of the class and remarks that help you understand the course content. You notice interesting conversations going on at the bulletin board. Students are making comments and other students are adding their own comment. Sometimes these comments form long connected discussions.