This has actually been a part of Sharepoint for the last few years. It's called Excel Services (http://msdn.microsoft.com/en-us/library/ms517343.aspx http://ms

This has actually been a part of Sharepoint for the last few years. It's called Excel Services (http://msdn.microsoft.com/en-us/library/ms517343.aspx http://msdn.microsoft.com/en-us/library/ms517343.aspx). It's very clever that they extended it to SkyDrive.