case 'trackback':
            $notify_message  = sprintf( __('A new trackback on the post #%1$s "%2$s" is waiting for your approval'), $post->ID, $post->post_title ) . "\r\n";
            $notify_message .= get_permalink($comment->comment_post_ID) . "\r\n\r\n";
            $notify_message .= sprintf( __('Website : %1$s (IP: %2$s , %3$s)'), $comment->comment_author, $comment->comment_author_IP, $comment_author_domain ) . "\r\n";
            $notify_message .= sprintf( __('URL    : %s'), $comment->comment_author_url ) . "\r\n";