From your Your Stuff > Preferences page, you can set discussion replies and content comments to display all on one level (flat) or indented hierarchically (threaded).
Flat views display comments and replies chronologically in the order they were received, and there is no indentation between responses. This view can be helpful if you like to see comments in the order they were made. However, it can become difficult to follow conversations between people when a discussion is longer than a few comments.
In a threaded view, you can see which post a person is responding to because comments and replies appear indented beneath the post and with arrows to indicate embedded replies or comments. This can help you follow conversations because responses remain associated together visually.
To set up your view style preferences, go to Your Stuff > Preferences . On the General Preferences tab, select your Discussion View and Comment View styles, and then click Save.