Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 11905)
+++ wp-includes/post.php	(working copy)
@@ -532,6 +532,8 @@
 
 	wp_cache_delete($post_id, 'post_meta');
 
+	do_action( 'added_post_meta', $wpdb->insert_id, $post_id, $meta_key, $meta_value );
+
 	return true;
 }
 
@@ -573,12 +575,16 @@
 	if ( !$meta_id )
 		return false;
 
+	do_action( 'delete_post_meta', $meta_id, $post_id, $meta_key, $meta_value );
+
 	if ( empty( $meta_value ) )
 		$wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = %s", $post_id, $meta_key ) );
 	else
 		$wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = %s AND meta_value = %s", $post_id, $meta_key, $meta_value ) );
 
 	wp_cache_delete($post_id, 'post_meta');
+	
+	do_action( 'deleted_post_meta', $meta_id, $post_id, $meta_key, $meta_value );
 
 	return true;
 }
@@ -651,9 +657,9 @@
 	if ( !$meta_key )
 		return false;
 
-	if ( ! $wpdb->get_var( $wpdb->prepare( "SELECT meta_key FROM $wpdb->postmeta WHERE meta_key = %s AND post_id = %d", $meta_key, $post_id ) ) ) {
+	$meta_id = $wpdb->get_var( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE meta_key = %s AND post_id = %d", $meta_key, $post_id ) );
+	if ( ! $meta_id )
 		return add_post_meta($post_id, $meta_key, $meta_value);
-	}
 
 	$meta_value = maybe_serialize( stripslashes_deep($meta_value) );
 
@@ -665,8 +671,13 @@
 		$where['meta_value'] = $prev_value;
 	}
 
+	do_action( 'update_post_meta', $meta_id, $post_id, $meta_key, $meta_value );
+	
 	$wpdb->update( $wpdb->postmeta, $data, $where );
 	wp_cache_delete($post_id, 'post_meta');
+	
+	do_action( 'updated_post_meta', $meta_id, $post_id, $meta_key, $meta_value );
+	
 	return true;
 }
 
Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php	(revision 11905)
+++ wp-includes/user.php	(working copy)
@@ -307,6 +307,11 @@
 		$meta_value = serialize($meta_value);
 	$meta_value = trim( $meta_value );
 
+	$cur = $wpdb->get_row( $wpdb->prepare("SELECT * FROM $wpdb->usermeta WHERE user_id = %d AND meta_key = %s", $user_id, $meta_key) );
+
+	if ( $cur && $cur->umeta_id )
+		do_action( 'delete_usermeta', $cur->umeta_id, $user_id, $meta_key, $meta_value );
+
 	if ( ! empty($meta_value) )
 		$wpdb->query( $wpdb->prepare("DELETE FROM $wpdb->usermeta WHERE user_id = %d AND meta_key = %s AND meta_value = %s", $user_id, $meta_key, $meta_value) );
 	else
@@ -314,6 +319,9 @@
 
 	wp_cache_delete($user_id, 'users');
 
+	if ( $cur && $cur->umeta_id )
+		do_action( 'deleted_usermeta', $cur->umeta_id, $user_id, $meta_key, $meta_value );
+
 	return true;
 }
 
@@ -399,6 +407,10 @@
 	}
 
 	$cur = $wpdb->get_row( $wpdb->prepare("SELECT * FROM $wpdb->usermeta WHERE user_id = %d AND meta_key = %s", $user_id, $meta_key) );
+
+	if ( $cur )
+		do_action( 'update_usermeta', $cur->umeta_id, $user_id, $meta_key, $meta_value );
+
 	if ( !$cur )
 		$wpdb->insert($wpdb->usermeta, compact('user_id', 'meta_key', 'meta_value') );
 	else if ( $cur->meta_value != $meta_value )
@@ -408,6 +420,11 @@
 
 	wp_cache_delete($user_id, 'users');
 
+	if ( !$cur ) 
+		do_action( 'added_usermeta', $wpdb->insert_id, $user_id, $meta_key, $meta_value );
+	else
+		do_action( 'updated_usermeta', $cur->umeta_id, $user_id, $meta_key, $meta_value );
+
 	return true;
 }
 
Index: wp-admin/includes/plugin.php
===================================================================
--- wp-admin/includes/plugin.php	(revision 11905)
+++ wp-admin/includes/plugin.php	(working copy)
@@ -314,8 +314,10 @@
 		@include(WP_PLUGIN_DIR . '/' . $plugin);
 		$current[] = $plugin;
 		sort($current);
+		do_action( 'activate_plugin', trim( $plugin) );
 		update_option('active_plugins', $current);
-		do_action('activate_' . $plugin);
+		do_action( 'activate_' . trim( $plugin ) );
+		do_action( 'activated_plugin', trim( $plugin) );
 		ob_end_clean();
 	}
 
@@ -343,9 +345,14 @@
 		$plugin = plugin_basename($plugin);
 		if( ! is_plugin_active($plugin) )
 			continue;
+		if ( ! $silent )
+			do_action( 'deactivate_plugin', trim( $plugin ) );
 		array_splice($current, array_search( $plugin, $current), 1 ); // Fixed Array-fu!
-		if ( ! $silent ) //Used by Plugin updater to internally deactivate plugin, however, not to notify plugins of the fact to prevent plugin output.
-			do_action('deactivate_' . trim( $plugin ));
+		//Used by Plugin updater to internally deactivate plugin, however, not to notify plugins of the fact to prevent plugin output.
+		if ( ! $silent ) {
+			do_action( 'deactivate_' . trim( $plugin ) );
+			do_action( 'deactivated_plugin', trim( $plugin ) );
+		}
 	}
 
 	update_option('active_plugins', $current);