diff --git a/app/models/card.rb b/app/models/card.rb
index a1d8e5115..4344d89b1 100644
--- a/app/models/card.rb
+++ b/app/models/card.rb
@@ -31,8 +31,4 @@ class Card < ApplicationRecord
   def cache_key
     [ super, collection.name ].compact.join("/")
   end
-
-  def was_mentioned(mention)
-    watch_by(mention.mentionee)
-  end
 end