This policy setting controls whether Excel 2007 saves hidden data to maintain formulas when a workbook is saved as a Web page that uses Office Web Components (OWC), which is being discontinued in Excel 2007.
If you enable this policy setting, when users save workbooks as Web pages that use OWC, Excel maintains externally referenced data of formulas that are not in the selected range to be published, which increases the size of the files and in some cases increases the risk of exposing sensitive information.
If you disable this policy setting, users will not be able to save hidden data to maintain formulas when publishing a workbook as a Web page that uses OWC. Excel 2007 replaces the formulas with calculated values.
If you do not configure this policy setting, the behavior of Excel 2007 is the same as Enabled; however, users can change this functionality by clearing the "Save any additional hidden data necessary to maintain formulas" user interface option under Excel Options | Advanced | General | Web Options dialog box | General Tab | Compatibility.