Guest Access Defined
With guest access, people who do not have accounts on the institution's Blackboard system can access the system and, if allowed, can access certain areas of course Web sites. Also, people who have user accounts on the system can access certain areas of course Web sites in which they are not enrolled.
Managing Guest Access to Course Areas
The most fundamental level of managing guest access is the "Secure" option for areas of course Web sites. In Blackboard, "secure" means access is limited to enrolled members of the course.
If Guest Access is enabled for the course, then unsecured areas can be accessed by any authenticated user or by anyone logged in to the system using the Preview button on the gateway or login page.

The security setting of areas in a course site can be controlled by the course's Instructor, Course Builder, or Teaching Assistant through Area Availability in Control Panel > Course Settings. Checking the box in the "Secure" column will secure that area of the course site so that only enrolled course members can access that area.

There are some security settings for course areas that cannot be changed. The Announcements area, because it is the default entry point to the course, cannot be secured. The Communication areas, including Virtual Classroom, Discussion Board, and Groups, are always secured and cannot be unsecured. Similarly, the Tools area is always secured so only enrolled users can access Student Tools.
Guest access to courses is utilized at many higher education institutions to allow prospective students to browse course offerings. Matriculated students who are deciding what courses to take for the following semester can also use the Preview option to look at course syllabi, view instructor contact information, or read about interesting projects in areas that instructors have chosen to leave unsecured in courses that allow guest access. Using Area Availability settings, an Instructor can choose which areas of the course will be public to prospective students and which areas can only be accessed by current students.
Controlling Guest Access to an Entire Course Site
In some circumstances, it may not be appropriate for Guests to access any part of a course at all. In these situations, the Guest Access course property can be disabled for the entire course. Instructors can control Guest Access from the Course Settings area of the Control Panel.

If Guest Access is set to "No," then the entire course site is secured, and only enrolled users may enter the course site. With this setting, the security settings of individual areas don't matter, because no guest will be able to access the course at all. This also applies to authenticated users who are not enrolled in the course.
If Guest Access is set to "Yes" for the course, then a Preview button will appear next to the course listing in the Course Catalog, as illustrated below.

By clicking on the Preview button or on the course title, guests and authenticated users may enter the course and view any areas that are unsecured. Guests cannot access the secured areas.
Modified from a document created by Blackboard.com