SimplyHelpful was a plugin used in legacy rails apps for generating the right dom id, css classes for records. For more info read http://juixe.com/techknow/index.php/2007/04/03/simply-helpful-rails-plugin/. However, Simplyhelpful is now in rails. So you will no longer need the plugin. And methods like dom_id are available out of the box now. Just get the scoping correct.
To give a specific example, for the dom_id method, usages may have been in helpers or views, and in that case you may get errors where Rails starts looking for dom_id method under ActionView. You will have to fix this. You need the RecordIdentifier module of ActionController.