How to Reply to a YouTube Comment
While watching most YouTube videos, you are given the opportunity to post a comment. Other YouTube viewers can also see your comments, and they may respond to you. Your YouTube account has an inbox that stores any comments made to you. If you would like to see and respond to these comments, access your YouTube inbox.
Log in to YouTube. Click in the drop-down menu next to the "Sign Out" link at the top of the screen. This displays a list of navigational options.
Click the "Inbox" option to load your messages. Click the "Comments" link on the left pane. This displays all comments you have received on the right pane.
Click the link to the comment found in the "Subject" column. This expands the comment, and displays a link to the YouTube video where the comment is located.
Click the YouTube video link. This takes you directly to the video containing the posted comment. Click the "Reply" button next to the comment.
Type your message, and click the "Post" button. You have now replied to the comment.