Comments allow a conversation to happen around one topic. This is particularly useful if a question needs to be answered with a questions, therefore prompting further replies. These can be handled as a thread by doing the following.
When the question comes in, you can choose to enable comments. To do so, at the bottom of the page, check “Allow comments”.
This will allow users to reply inline. When they respond, it will not appear as a new question. instead there is a “Pending Comments” column in the question list that will highlight any additions to the thread.
Clicking on the highlighted speech bubble will take you to a moderation screen.
If you would like to add to the conversation, edit the question and scroll to the bottom of the page. Pressing the “Add Comment” button will allow you to leave an inline reply.