Discussions allow users to have interactive conversations with groups or an entire class. Discussions can be created as a graded assignment for students, or they can be ungraded and serve as a general forum. They can also be created to be focused or threaded.
Focused discussions only allow for two levels of nesting, the original post and subsequent replies, and are best suited for short-lived conversations. Threaded discussions allow for infinite levels of nesting replies and are best suited for longer conversations.