Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php	(revision 21842)
+++ wp-includes/user.php	(working copy)
@@ -488,7 +488,7 @@
 				elseif ( preg_match('|^https?://|', $search) && ! wp_is_large_network( 'users' ) )
 					$search_columns = array('user_url');
 				else
-					$search_columns = array('user_login', 'user_nicename');
+					$search_columns = array('user_login', 'user_nicename', 'display_name', 'user_email');
 			}
 
 			$this->query_where .= $this->get_search_sql( $search, $search_columns, $wild );