http://wordpress.stackexchange.com/questions/121354/use-comments-as-notes-visible-for-comment-author-only

wpse-121354.php

<?php
if ( ! function_exists( '_s_comment' ) ) :
/**
 * Template for comments and pingbacks.
 *
 * Used as a callback by wp_list_comments() for displaying the comments.
 */
function _s_comment( $comment, $args, $depth ) {
	$GLOBALS['comment'] = $comment;

	$current_user_id = get_current_user_id();

	if ( 'pingback' == $comment->comment_type || 'trackback' == $comment->comment_type ) : ?>

	<li id="comment-<?php comment_ID(); ?>" <?php comment_class(); ?>>
			<div class="comment-body">
					<?php _e( 'Pingback:', '_s' ); ?> <?php comment_author_link(); ?> <?php edit_comment_link( __( 'Edit', '_s' ), '<span class="edit-link">', '</span>' ); ?>
			</div>

	<?php elseif ( $current_user_id == $comment->user_id ) : ?>

	<li id="comment-<?php comment_ID(); ?>" <?php comment_class( empty( $args['has_children'] ) ? '' : 'parent' ); ?>>
			<article id="div-comment-<?php comment_ID(); ?>" class="comment-body">
					<footer class="comment-meta">
							<div class="comment-author vcard">
									<?php if ( 0 != $args['avatar_size'] ) { echo get_avatar( $comment, $args['avatar_size'] ); } ?>
									<?php printf( __( '%s <span class="says">says:</span>', '_s' ), sprintf( '<cite class="fn">%s</cite>', get_comment_author_link() ) ); ?>
							</div><!-- .comment-author -->

							<div class="comment-metadata">
									<a href="<?php echo esc_url( get_comment_link( $comment->comment_ID ) ); ?>">
											<time datetime="<?php comment_time( 'c' ); ?>">
													<?php printf( _x( '%1$s at %2$s', '1: date, 2: time', '_s' ), get_comment_date(), get_comment_time() ); ?>
											</time>
									</a>
									<?php edit_comment_link( __( 'Edit', '_s' ), '<span class="edit-link">', '</span>' ); ?>
							</div><!-- .comment-metadata -->

							<?php if ( '0' == $comment->comment_approved ) : ?>
							<p class="comment-awaiting-moderation"><?php _e( 'Your comment is awaiting moderation.', '_s' ); ?></p>
							<?php endif; ?>
					</footer><!-- .comment-meta -->

					<div class="comment-content">
							<?php comment_text(); ?>
					</div><!-- .comment-content -->

					<?php
							comment_reply_link( array_merge( $args, array(
									'add_below' => 'div-comment',
									'depth'     => $depth,
									'max_depth' => $args['max_depth'],
									'before'    => '<div class="reply">',
									'after'     => '</div>',
							) ) );
					?>
			</article><!-- .comment-body -->

	<?php
	endif;
}
endif; // ends check for _s_comment()