Topics allow you to categorize posts and filter for posts on the basis of subject matter. They are typically set up by an instructor before a course begins. If your instructor has enabled topics, you can select a topic when you create a Post by clicking Topics in the post toolbox and selecting the relevant topic. Depending on your instructor's settings, you may be required to add a topic whenever you create a post.
To filter by topic, click on a topic tag on a post or comment.
Alternatively, select the Topics filter from the feed toolbar. You can type the name of the topic you want to filter by, or you can choose the topic from the drop-down menu.
Only instructors can create topics, and you can filter by a topic only if that topic has already been tagged to a post. If you feel a topic may be useful, you can suggest it to the instructor, or you can use hashtags to organize or flag specific content.