Other YouTube users can post comments on your videos and your channel (if the Discussion tab is enabled for your channel). Since it's your content, you have some tools to moderate the discussion.
Take action on comments. Click the arrow in the upper right of a comment on your channel or video to see your options.
- Remove takes down the comment from YouTube. If the comment has any replies, they will also be removed. Note that if the comment was also shared on Google+, it will still be live there.
- Ban from channel blocks the user from posting comments on videos and your channel. You can remove the user from the banned list later (see below).
Hold comments for approval. You can require approval for all new comments before they're posted to your video or channel:
- Video comments - Find the video in the Video Manager, click Edit under the video, and click Advanced Settings. Then, under “Allow comments”, select Approved. You can also choose the default moderation settings for new videos in your comments settings.
- Channel comments - You can turn this on for your channel in your Channel Navigation settings.
When someone comments, you'll get a notification as well as a blue banner on the channel or video. You can then review the comments to approve, delete, or flag them for abuse or spam.
Approved users and banned users. In your comments settings, you'll find a list of approved users and banned users. Approved users' comments will automatically be approved and shown, even if you've chosen to hold comments for approval. Banned users' comments will never be shown. You can add or remove individual users or Google+ Circles.
Blacklist. In your comments settings, you can specify a comma separated list of words and phrases. Comments closely matching these terms will be held for your approval (unless they were posted by someone on your approved user list).
Spam filtering. If someone leaves a comment that looks like spam, a blue banner on the channel or video will let you know. You can then review these comments to either delete them or approve them if they're not actually spam.