diff --git a/lib/impressionist/models/mongoid/impression.rb b/lib/impressionist/models/mongoid/impression.rb
index 01e8524..5e10e33 100644
--- a/lib/impressionist/models/mongoid/impression.rb
+++ b/lib/impressionist/models/mongoid/impression.rb
@@ -19,6 +19,7 @@ class Impression
   field :session_hash
   field :message
   field :referrer
+  field :params
 
   after_save :impressionable_counter_cache_updatable?