Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 21427)
+++ wp-includes/comment.php	(working copy)
@@ -1326,6 +1326,7 @@
  *
  * @since 1.5.0
  * @uses apply_filters() Calls 'preprocess_comment' hook on $commentdata parameter array before processing
+ * @uses apply_filters() Calls 'notify_postauthor' hook on get_option('comments_notify') before processing
  * @uses do_action() Calls 'comment_post' hook on $comment_ID returned from adding the comment and if the comment was approved.
  * @uses wp_filter_comment() Used to filter comment before adding comment.
  * @uses wp_allow_comment() checks to see if comment is approved.
@@ -1367,7 +1368,9 @@
 
 		$post = &get_post($commentdata['comment_post_ID']); // Don't notify if it's your own comment
 
-		if ( get_option('comments_notify') && $commentdata['comment_approved'] && ( ! isset( $commentdata['user_id'] ) || $post->post_author != $commentdata['user_id'] ) )
+		$do_notify = apply_filters( 'notify_postauthor', get_option( 'comments_notify' ), $comment_ID );
+
+		if ( $do_notify && $commentdata['comment_approved'] && ( ! isset( $commentdata['user_id'] ) || $post->post_author != $commentdata['user_id'] ) )
 			wp_notify_postauthor($comment_ID, isset( $commentdata['comment_type'] ) ? $commentdata['comment_type'] : '' );
 	}
 
@@ -1382,6 +1385,7 @@
  *
  * @since 1.0.0
  * @uses wp_transition_comment_status() Passes new and old comment status along with $comment object
+ * @uses apply_filters() Calls 'notify_postauthor' hook on get_option('comments_notify') before processing
  *
  * @param int $comment_id Comment ID.
  * @param string $comment_status New comment status, either 'hold', 'approve', 'spam', or 'trash'.
@@ -1400,7 +1404,7 @@
 		case 'approve':
 		case '1':
 			$status = '1';
-			if ( get_option('comments_notify') ) {
+			if ( apply_filters( 'notify_postauthor', get_option( 'comments_notify' ), $comment_id ) ) {
 				$comment = get_comment($comment_id);
 				wp_notify_postauthor($comment_id, $comment->comment_type);
 			}