diff --git a/app/models/user.rb b/app/models/user.rb
index cb15023..0cc2939 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -87,7 +87,8 @@ class User < ActiveRecord::Base
 
   def avatar_url(size = 100)
     "https://secure.gravatar.com/avatar/" +
-      Digest::MD5.hexdigest(self.email.strip.downcase) + "?r=pg&d=mm&s=#{size}"
+      Digest::MD5.hexdigest(self.email.strip.downcase) +
+      "?r=pg&d=identicon&s=#{size}"
   end
 
   def average_karma