If you ever need to understand what the WSS_WPG or WSS_ADMIN_WPG groups can and can’t do in SharePoint – look no further! The articles linked below outline their rights in great detail. It not only details what groups the various service accounts in SharePoint belong to, but also what permissions those groups have over data stores like the registry and file system. Awesome.

SharePoint 2007 and WSS

• http://technet.microsoft.com/en-us/library/cc678863(v=office.12).aspx

SharePoint 2010 and Foundation

• http://technet.microsoft.com/en-us/library/cc678863(v=office.14).aspx