YouTube Now permits you to Erase your unwanted Comments
If you’ve ever made silly a comment on a YouTube video or got into a “verbal fight” with some other user – and now regret all that, YouTube now permits you to delete your unwanted comments that cause you embarrassment. If is was a typo you can delete it and make anther comment, but you can’t edit/modify previously made comments.
This new feature is already functioning, so if you have any comments in mind, then login into your account and start deleting.
via [YouTube Blog]