Support for user data in the data for grid. In jqGrid it is done like this http://www.trirand.com/jqgridwiki/doku.php?id=wiki:retrieving_data. Certain messages while showing data, like server errors, or data related to any other component which depends on grid data but not meant to be displayed inside the grid can be passed using this feature. I usually pass number of rows updated, error messages, or confirmation messages. This is because both edit and search urls are controlled by jqGrid plugin and is hard to intercept when they are sent out or received back in.
Grid to Form, Form to Grid - http://www.trirand.com/jqgridwiki/doku.php?id=wiki:form_editing#formtogrid. This feature may be covered as part of row data editing. I understand observable data might be enabling this. But I feel it is very often required to view the data in a form in editable and/or just viewable form.