It’s important to note that although Discussions are a student engagement and assessment tool, that there is functionality within the tool that allow you to guide the conversation, to refocus tangents, and to provide clarifications.
Canvas guides (bCourses) have identified two types discussion forums (using the same tool of course): focused discussions and threaded discussions.
Taken from the Canvas Resource page What are Discussions,
Focused Discussions are relatively short-lived interactions that tend to disappear as the course progresses, such as a weekly forum for questions related to that week’s activities.
Use a Focused Discussion for single posts and related comments. One discussion leader typically posts a message and multiple learners comment on it. Participants may leave a side comment to a reply, but cannot develop the conversation beyond two layers of nesting.
When looking at Discussion Forum settings, you’ll notice that there is no box to click to make it a focused discussion. What makes it a focused discussion is the way you apply the tool and the parameters set around it. For example, weekly discussions in every module are focused because they’re aligned with a specific module or week, have a due date, and will be closed for comments after that due date. Let’s look at the difference with a threaded discussion.
Again, getting back to the Canvas resource,
Threaded Discussions lend themselves to the refining of complex ideas. Responses and different lines of inquiry that can be quickly navigated due to its hierarchical structure. Threaded Discussions may be long-standing spaces for thoughts that persist throughout an entire course.
Use a Threaded Discussion for multiple posts and related comments. One or more discussion leaders post a message and multiple learners comment on it with the freedom to create any number of related discussion topics and comments (infinite layers of nesting).
The passage implies that the difference between a threaded discussion and a focused discussion is that threaded discussions lend themselves to “infinite layers of nesting.”
Again, the difference is in how the tool is used and how the experience is facilitated. For example, if you wanted your course to have nothing but focused discussions as they are embedded in the modules, you can remove the Discussion link from the navigation panel in your course. However, if you want to have longstanding threaded discussion boards, you can leave the link in the panel and post your discussions in the Discussions Index Page of your bCourse site and not in the module. Of course, there’s nothing to stop you if you wanted to do both.