Index: wp-includes/ms-functions.php
===================================================================
--- wp-includes/ms-functions.php	(revision 23297)
+++ wp-includes/ms-functions.php	(working copy)
@@ -1748,13 +1748,12 @@
  */
 function is_user_spammy( $username = 0 ) {
 	if ( $username == 0 ) {
-		$user_id = get_current_user_id();
+		$user = get_user_by( 'id', get_current_user_id() );
 	} else {
-		$user_id = get_user_id_from_string( $username );
+		$user = get_user_by( 'login', $username );
 	}
-	$u = get_userdata( $user_id );
 
-	return ( isset( $u->spam ) && $u->spam == 1 );
+	return ( isset( $user->spam ) && $user->spam == 1 );
 }
 
 /**
@@ -2013,4 +2012,4 @@
 		return min( $size, $fileupload_maxk );
 
 	return min( $size, $fileupload_maxk, get_upload_space_available() );
-}
\ No newline at end of file
+}