将SharePoint集与文件系统同步？

Does anyone out there find it useful to sync' SharePoint sets (lists, documents, etc.) with "external" sources like the file system? What about SharePoint-to-SharePoint sync? Do we have any explanation why Microsoft Sync Framework lacks any serious hooks into SharePoint? Is this stuff coming out in some Office 14 timeframe? Under NDA?Does anyone out there find it useful to sync' S