Instructors can use the create blogs using the Blog tool.
A blog—a shorthand term that means web log—is a personal online journal that is frequently updated and intended for general public access and use. Most blogs also have some kind of commenting system, so that people can respond to and interact with one another. Blogs encourage students to clearly express their ideas and addresses the need to expand various aspects of social learning. Moreover, they are an effective means of gaining insight into students' activities and provide a way to share the knowledge and materials collected.
In Blackboard Learn, instructors create and manage blogs, and only enrolled users can view and create entries and comments in them.
Visit Blackboard help; Blogs for more information.