diff --git a/plus1.module b/plus1.module
index 5b97215..7044c0b 100644
--- a/plus1.module
+++ b/plus1.module
@@ -142,6 +142,7 @@ function plus1_vote($entity_type, $entity_id, $tag = 'plus1_node_vote') {
       'value_type' => 'points',
       'value' => 1,
       'tag' => $tag ? $tag : 'plus1_' . $entity_type . '_vote',
+      'vote_source' => $user->uid ? $user->uid : ip_address(),
     );
     votingapi_set_votes($votes);
     $criteria = array(