Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 6256)
+++ wp-includes/comment.php	(working copy)
@@ -752,6 +752,15 @@
 }
 
 
+// Don't self-ping by Michael D. Adams
+function no_self_ping( &$links ) {
+	$home = get_option( 'home' );
+	foreach ( $links as $l => $link )
+		if ( 0 === strpos( $link, $home ) )
+			unset($links[$l]);
+}
+
+
 function privacy_ping_filter($sites) {
 	if ( '0' != get_option('blog_public') )
 		return $sites;
Index: wp-includes/default-filters.php
===================================================================
--- wp-includes/default-filters.php	(revision 6256)
+++ wp-includes/default-filters.php	(working copy)
@@ -133,6 +133,7 @@
 add_filter('comment_flood_filter', 'wp_throttle_comment_flood', 10, 3);
 add_filter('pre_comment_content', 'wp_rel_nofollow', 15);
 add_filter('comment_email', 'antispambot');
+add_filter('pre_ping', 'no_self_ping');
 
 // Actions
 add_action('wp_head', 'rsd_link');