This policy setting controls whether users can edit and save Office 2010 documents on Web servers that they have opened using ...

This policy setting controls whether users can edit and save Office 2010 documents on Web servers that they have opened using Internet Explorer.
      
If enable this policy setting, when users browse to an Office 2010 document on a Web server using Internet Explorer the appropriate application opens the file in read/write mode.

If you disable or do not configure this policy setting, when users browse to an Office 2010 document on a Web server using Internet Explorer, the appropriate application opens the file in read-only mode.